2022/09/28 更新

写真a

ウエダ ケンジ
植田 研二
所属
理工学術院 大学院情報生産システム研究科
職名
教授

学位

  • 2000年03月   大阪大学   博士(理学)

経歴

  • 2022年04月
    -
    継続中

    早稲田大学   大学院情報生産システム研究科   教授

  • 2022年06月
    -
    2023年03月

    東海国立大学機構名古屋大学   大学院工学研究科   客員教授

  • 2017年04月
    -
    2022年03月

    名古屋大学   大学院工学研究科 物質科学専攻 物質デバイス機能創成学   准教授

  • 2009年04月
    -
    2017年03月

    名古屋大学   大学院工学研究科 結晶材料工学専攻   准教授

  • 2011年03月
    -
    2011年08月

    フランスCNRS、ネール研究所、客員研究員

  • 2001年02月
    -
    2009年03月

    NTT物性科学基礎研究所   研究員

  • 2000年04月
    -
    2001年01月

    大阪大学産業科学研究所   博士研究員(日本学術振興会特別研究員PD(COE))

  • 1998年04月
    -
    2000年03月

    日本学術振興会特別研究員(DC2)

  • 1996年04月
    -
    1997年01月

    東芝生産技術研究所   研究員

▼全件表示

所属学協会

  •  
     
     

    日本応用物理学会

  •  
     
     

    ニューダイヤモンドフォーラム

  •  
     
     

    日本金属学会

  •  
     
     

    日本磁気学会

 

研究分野

  • 電子デバイス、電子機器

  • 薄膜、表面界面物性

  • ナノ材料科学

研究キーワード

  • 薄膜機能材料

  • 半導体材料・デバイス

  • 無機炭素材料

論文

  • Structural insight using anomalous XRD into Mn2CoAl Heusler alloy films grown by magnetron sputtering, IBAS, and MBE techniques

    Hiroo Tajiri, Loku Singgappulige Rosantha Kumara, Yuya Sakuraba, Zixi Chen, Jian Wang, Weinan Zhou, Kushwaha Varun, Kenji Ueda, Shinya Yamada, Kohei Hamaya, Kazuhiro Hono

    Acta Materialia   235   118063 - 118063  2022年08月  [査読有り]

    DOI

  • Optoelectronic synapses using vertically aligned graphene/diamond heterojunctions

    Y. Mizuno, Y. Ito, K. Ueda

    Carbon   182   669 - 676  2021年09月  [査読有り]

    DOI

  • Spin-Orbit-Torque Switching of Noncollinear Antiferromagnetic Antiperovskite Manganese Nitride

    T. Hajiri, K. Matsuura, K. Sonoda, E. Tanaka, K. Ueda, H. Asano

    Physical Review Applied   16 ( 2 )  2021年08月  [査読有り]

    DOI

  • Fabrication of high-quality epitaxial Bi1-xSbx films by two-step growth using molecular beam epitaxy

    K. Ueda, Y. Hadate, K. Suzuki, H. Asano

    Thin Solid Films   713   138361-1-8  2020年09月  [査読有り]

  • Multibit optoelectronic memory using graphene/diamond (carbon sp2-sp3) heterojunctions and its arithmetic functions

    K. Ueda, Y. Mizuno, H. Asano

    Appl. Phys. Lett.   117   092103-1-5  2020年09月  [査読有り]

  • Photomemristors using carbon nanowall/diamond heterojunctions

    K. Ueda, H. Itou, H. Asano

    J. Mater. Res.   34   626-633  2019年02月  [査読有り]

  • Strain effect on magnetic property of antiferromagnetic insulator SmFeO3

    M. Kuroda, N. Tanahashi, T. Hajiri, K. Ueda, H. Asano

    AIP Advances   8   055814-1-4  2018年  [査読有り]

  • Ambipolar transport in Mn2CoAl films by ionic liquid gating

    Kenji Ueda, Shingo Hirose, Hidefumi Asano

    APPLIED PHYSICS LETTERS   110 ( 20 ) 202405-1-4  2017年05月  [査読有り]

     概要を見る

    We demonstrate ambipolar transport and modulation of electronic properties of Mn2CoAl (MCA), one of the most promising candidates for spin gapless semiconductors (SGSs), by using ionic liquid gating in electronic double-layer transistors. The carrier concentration and mobility of MCA films were systematically changed with carrier polarity inversion from the p- to the n-type by the gating technique. The ambipolar transport is one of the most significant properties of SGSs and strongly promotes the gapless features of MCA. The present results pave the way for the use of MCA as a spin source of both spin-polarized electrons and holes. Published by AIP Publishing.

    DOI

  • BaySr1-yTiO3 buffer layers for strain tuning of infinite-layer Sr1-xLaxCuO2 thin films

    K. Sakuma, M. Ito, Y. He, T. Hajiri, K. Ueda, H. Asano

    Thin Solid Films   612   8  2016年05月  [査読有り]

  • Magnetization reversal of the domain structure in the anti-perovskite nitride Co3FeN investigated by high-resolution X-ray microscopy

    T. Hajiri, S. Finizio, M. Vafaee, Y. Kuroki, H. Ando, H. Sakakibara, A. Kleibert, L. Howald, F. Kronast, K. Ueda, H. Asano, M. Klaeui

    JOURNAL OF APPLIED PHYSICS   119 ( 18 ) 183901  2016年05月  [査読有り]

     概要を見る

    We performed X-ray magnetic circular dichroism (XMCD) photoemission electron microscopy imaging to reveal the magnetic domain structure of anti-perovskite nitride Co3FeN exhibiting a negative spin polarization. In square and disc patterns, we systematically and quantitatively determined the statistics of the stable states as a function of geometry. By direct imaging during the application of a magnetic field, we revealed the magnetic reversal process in a spatially resolved manner. We compared the hysteresis on the continuous area and the square patterns from the magnetic field-dependent XMCD ratio, which can be explained as resulting from the effect of the shape anisotropy, present in nanostructured thin films. Published by AIP Publishing.

    DOI

  • Photo-controllable memristive behavior of graphene/diamond heterojunctions

    K. Ueda, S. Aichi, H. Asano

    APPLIED PHYSICS LETTERS   108 ( 22 ) 222102  2016年05月  [査読有り]

     概要を見る

    Graphene/diamond (carbon sp(2)-sp(3)) heterojunctions are demonstrated as photo-controllable memristors with photoswitchable multiple resistance states and nonvolatile memory functions. The ratio of conductivity change between the higher and lower resistance states of the junctions was similar to 10(3). The junctions exhibit light wavelength selectivity, and the resistance states can be switched only by blue or violet light irradiation. The mechanism for the change in photoconductivity is considered to be caused by oxidation-reduction of the graphene and/or graphene-diamond (sp(2)-sp(3)) interfaces through the movement of oxygen ions by bias with photo-irradiation because they have wavelength selectivity and require air exposure for several days to exhibit memristive behavior. These results indicate that graphene-diamond, carbon sp(2)-sp(3) heterojunctions can be used as photo-controllable devices with both photomemory and photoswitching functions. Published by AIP Publishing.

    DOI

  • Controlled superconductivity in infinite-layer Sr0.875La0.125CuO2 films sputter-deposited on BaySr1-yTiO3 buffer layers

    Keita Sakuma, Masataka Ito, Tetsuya Hajiri, Kenji Ueda, Hidefumi Asano

    APPLIED PHYSICS EXPRESS   9 ( 2 ) 023101  2016年02月  [査読有り]

     概要を見る

    We present a systematic study of the structural and electrical properties of electron-doped infinite-layer Sr0.875La0.125CuO2 (SLCO) thin films grown on BaySr1-yTiO3 (BSTO; y = 0.2-0.7) buffer layers. The BSTO (y = 0.2-0.6) buffer layers were found to allow the coherent growth of SLCO thin films. The coherently tensile-strained SLCO thin films grown on BSTO (y = 0.6) buffer layers at a low deposition rate of 0.2nm/min showed a low room-temperature resistivity (118 mu Omega cm) and a high T-c (36 K). All the other SLCO thin films exhibited a reduced T-c of around 20 K. The present results are discussed in terms of correlation among epitaxial strain, c(SLCO)/a(SLCO) ratio, and T-c. (C) 2016 The Japan Society of Applied Physics

    DOI

  • Strain Effect of a-Axis-Oriented Sr1-xLaxCuO2 Thin Films Grown on LaAlO3 Substrates

    Yilun He, Masataka Ito, Tetsuya Hajiri, Kenji Ueda, Hidefumi Asano

    IEEE TRANSACTIONS ON MAGNETICS   51 ( 11 ) 9000504  2015年11月  [査読有り]

     概要を見る

    The epitaxial thin films of electron-doped infinite-layer cuprate superconductor Sr1-xLaxCuO2 (SLCO; x = 0.1) were grown by dc magnetron sputtering, and their structural and electrical properties were systematically investigated by changing mismatch to substrate and SLCO film thickness, with a reduction annealing period under vacuum to remove the excess apex oxygen. Thin films of BaySr1-yTiO3 (BSTO) with y = 0.55, 0.6, and 0.7, prepared on (001) (La0.18Sr0.82)(Al0.59Ta0.41)O-3 substrates, were used as the epitaxial buffer layers to induce different levels of tensile strain in c-axis-oriented SLCO, while (001) LaAlO3 substrates were used for the growth of a-axis-oriented SLCO. The highest Tc value of c-axis oriented SLCO was obtained on the BSTO (y = 0.6) layers and the mismatch dependence of strain relaxation thickness was clarified. The strain in a-axis SLCO films was analyzed and controlled by changing the thickness of SLCO thin films. As a result, strong thickness dependence of superconducting properties was observed, and T-c(zero) was obtained in the a-axis SLCO for the first time. Based on these results, the strain effects of the SLCO film properties are discussed.

    DOI

  • Strain Effect of <inline-formula> <tex-math notation="LaTeX">$a$ </tex-math></inline-formula>-Axis-Oriented Sr1&#x2212;<italic>x</italic>La<italic>x</italic>CuO2 Thin Films Grown on LaAlO3 Substrates

    Yilun He, Masataka Ito, Tetsuya Hajiri, Kenji Ueda, Hidefumi Asano

    {IEEE} Transactions on Magnetics   51 ( 11 ) 1  2015年11月  [査読有り]

    DOI

  • Direct formation of graphene layers on diamond by high-temperature annealing with a Cu catalyst

    K. Ueda, S. Aichi, H. Asano

    Diamond Relat. Mater.   63   148  2015年10月  [査読有り]

  • High-temperature and high-voltage characteristics of Cu/diamond Schottky diodes

    K. Ueda, K. Kawamoto, H. Asano

    DIAMOND AND RELATED MATERIALS   57   28 - 31  2015年08月  [査読有り]

     概要を見る

    High-temperature and high-voltage characteristics of Cu/diamond Schottky diodes were investigated. Cu Schottky diodes showed clear rectification up to similar to 700 degrees C. The current-voltage characteristics of the diodes at 400 degrees C were almost unchanged after keeping them for 30 h, implying they have high stability at similar to 400 degrees C. The diodes showed specific on-resistance and breakdown voltage of 83.4m Omega cm(2) and 713 V at 400 degrees C, respectively, which are comparable to reported highest values for diamond Schottky diodes and close to the theoretical limit for 6H-SiC at several hundred degrees C. These results indicate that Cu/diamond Schottky diodes are promising for high-temperature power applications. (C) 2015 Elsevier B.V. All rights reserved.

    DOI

  • Magnetic properties and anisotropic magnetoresistance of antiperovskite nitride Mn3GaN/Co3FeN exchange-coupled bilayers

    H. Sakakibara, H. Ando, Y. Kuroki, S. Kawai, K. Ueda, H. Asano

    JOURNAL OF APPLIED PHYSICS   117 ( 17 ) 17D725-1-4  2015年05月  [査読有り]

     概要を見る

    Epitaxial bilayers of antiferromagnetic Mn3GaN/ferromagnetic Co3FeN with an antiperovskite structure were grown by reactive magnetron sputtering, and their structural, magnetic, and electrical properties were investigated. Exchange coupling with an exchange field H-ex of 0.4 kOe at 4K was observed for Mn3GaN (20 nm)/Co3FeN (5 nm) bilayers. Negative anisotropic magnetoresistance (AMR) effect in Co3FeN was observed and utilized to detect magnetization reversal in exchange-coupled Mn3GaN/Co3FeN bilayers. The AMR results showed evidence for current-induced spin transfer torque in antiferromagnetic Mn3GaN. (C) 2015 AIP Publishing LLC.

    DOI

  • Low temperature growth of Co2MnSi films on diamond semiconductors by ion-beam assisted sputtering

    M. Nishiwaki, K. Ueda, H. Asano

    J. Appl. Phys.   117   17D719-1-4  2015年04月  [査読有り]

  • Preparation and properties of Sr0.9La0.1CuO2 thin films grown on BaySr1-yTiO3 layers

    Y. He, M. Ito, K. Sakuma, K. Ueda, H. Asano

    IEEE Trans. Appl. Super.   25   7501204-1-4  2015年01月  [査読有り]

  • Deposition and reduction of infinite-layer Sr1-xLaxCuO2 films

    Keita Sakuma, Yilun He, Kenji Ueda, Hidefumi Asano

    Japanese Journal of Applied Physics   54 ( 5 ) 053101-1-4  2015年  [査読有り]

     概要を見る

    Electron-doped infinite-layer (IL) Sr1-xLaxCuO2thin films were grown on bare and lattice-matched Ba0.55Sr0.45TiO3-buffered LaAlO3(100) substrates by magnetron sputtering, and their structures and electrical properties were investigated systematically for various deposition and reduction conditions. The a- and c-axis-oriented films were obtained on LaAlO3and LaAlO3//Ba0.55Sr0.45TiO3substrates, respectively. For the caxis-oriented films, short-time (&lt
    6 min) reduction annealing in vacuum followed by deposition was effective for the removal of excess apical oxygen that was incorporated during deposition. The removal of excess apical oxygen was evidenced by the shortened c-axis and the appearance of superconductivity. However, subsequent annealing led to the elongation of the c-axis and loss of superconductivity. The a-axis-oriented films exhibited a similar behavior, although the time scale of such films for reduction annealing was significantly larger than that of the c-axis films. The implications of these results are discussed in terms of the oxygen sublattice in the IL compound.

    DOI

  • Preparation and Properties of Ferromagnetic Antiperovskite Co3FeN Thin Films

    Hideki Sakakibara, Hiroki Ando, Tetsuya Miyawaki, Kenji Ueda, Hidefumi Asano

    IEEE TRANSACTIONS ON MAGNETICS   50 ( 11 ) 2600404-1-4  2014年11月  [査読有り]

     概要を見る

    Thin films of Co3FeN with an antiperovskite structure were epitaxially grown on (La0.18Sr0.82)(Al0.59Ta0.41)O-3 (001) substrates by reactive magnetron sputtering. The influence of the N-2 volume concentration in the sputtering gas mixture on the structure and properties of Co3FeN thin films was systematically investigated. The optimized Co3FeN thin films exhibited a saturation magnetization, M-s, of 1350 emu/cc, which is comparable with the theoretical value. A negative anisotropic magnetoresistance (AMR) effect with an AMR ratio of up to -0.88% was observed at 4.2 K.

    DOI

  • Fabrication of epitaxial Co2MnSi films on lattice-matched MgAl2O4 substrates by ion-beam assisted sputtering

    K. Ueda, M. Nishiwaki, T. Soumiya, H. Asano

    Thin solid films   570   134-137  2014年10月  [査読有り]

  • High-temperature characteristics and stability of Cu/diamond Schottky diodes

    Kenji Ueda, Keita Kawamoto, Hidefumi Asano

    Japanese Journal of Applied Physics   53 ( 4 ) 04EP05-1-4  2014年  [査読有り]

     概要を見る

    The high-temperature electrical characteristics and stability of Cu/diamond Schottky diodes were examined and compared with those of Schottky diodes using Ag and Ni electrodes. The Cu/diamond Schottky diodes exhibited clear rectification up to 700 °C, indicating that high-temperature operation is possible using these diodes. This is thought to be due to their large Schottky barrier height of ∼1.6 eV. The high-temperature stability of the Cu/diamond Schottky diodes was better than that for diodes using Ag or Ni, probably because of less interfacial reaction or interdiffusion between the Cu and diamond. © 2014 The Japan Society of Applied Physics.

    DOI

  • Reactively sputtered MgAl2O4 barrier layers for Heusler tunnel junctions

    K. Inagaki, N. Fukatani, K. Mari, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   63 ( 3 ) 830 - 834  2013年08月  [査読有り]

     概要を見る

    Epitaxial MgAl2O4 thin films were deposited on a lattice-matched Heusler alloy, Fe2CrSi, by reactive magnetron sputtering of an MgAl2 target in an Ar+O-2 atmosphere. Epitaxial Fe2CrSi/MgAl2O4 junctions were obtained by inserting an ultrathin MgAl2 interlayer, which worked as a protective layer for oxidization at the surface of the Fe2CrSi. The growth of MgAl2O4 was found to be very sensitive to the MgAl2 thickness and the oxygen partial pressure during the deposition of MgAl2O4. Both epitaxial growth and characteristics of the efficient tunneling barrier were obtained in an Fe2CrSi/MgAl2O4 (3 nm)/CoFe tunneling device for MgAl2O4 thin films grown by reactive sputtering. The present epitaxial MgAl2O4 barrier deposited by reactive sputtering is expected to realize high performance spintronic devices.

    DOI

  • Fabrication and properties of double perovskite SrLaVRuO6

    Ryosuke Zenzai, Tetsuya Miyawaki, Kenji Ueda, Hidefumi Asano

    Journal of the Korean Physical Society   63 ( 3 ) 787 - 790  2013年08月  [査読有り]

     概要を見る

    Polycrystalline bulk and epitaxial thin film samples of double-perovskite SrLaVRuO6 were prepared, and their magnetic and electrical properties were investigated. Structural characterization on the bulk samples has revealed that a double-perovskite phase can be formed in coexistence with the secondary phase of nonmagnetic semiconducting Sr3V2O8. Magnetic and electrical investigations have shown that the double-perovskite SrLaVRuO6 compound is an antiferromagnetic metal. Moreover, it has been found that epitaxy using a lattice-matched substrate leads to suppression of the Sr3V2O8 secondary phase and promoting growth of phase-pure double-perovskite SrLaVRuO6. © 2013 The Korean Physical Society.

    DOI

  • Structural and magnetic properties of antiferromagnetic Heusler Ru2MnGe Epitaxial thin films

    Naoto Fukatani, Hirohito Fujita, Tetsuya Miyawaki, Kenji Ueda, Hidefumi Asano

    Journal of the Korean Physical Society   63 ( 3 ) 711 - 715  2013年08月  [査読有り]

     概要を見る

    Structural and magnetic properties were investigated for Heusler-type alloy Ru2MnGe thin films. Ru2MnGe films on MgO substrate were subjected to an in-plane compressive strain, and exhibited enhanced antiferromagnetic (AFM) transition temperature (T N) up to 353 K, which exceeds by 37 K from the cubic bulk material (T N = 316 K). We also observed the exchange coupling between Ru2MnGe and Heusler-type ferromagnetic (FM) half-metal Fe2CrSi thin films. The present AFM Heusler alloy with relatively high T N is useful to fabricate high-quality all Heusler-type half-metal AFM/FM junctions and is a promising material for the emerging field of AFM spintronics. © 2013 The Korean Physical Society.

    DOI

  • Inversion of magnetoresistance in La1-xSrxMnO3/Nb-doped SrTiO3/CoFe junctions

    K. Ueda, K. Tozawa, H. Asano

    Journal of the Korean Physical Society   63 ( 3 ) 706 - 710  2013年08月  [査読有り]

     概要を見る

    Magnetoresistance (MR) devices using degenerated oxide semiconductors, Nb-doped SrTiO3, (Nb-STO) as intermediate layers between two ferromagnets were fabricated and their magnetic and transport properties were evaluated. Magnetic junctions using the trilayer films showed MR of ∼5% at 4.2 K, and the sign and the magnitude of the MR were changed depending on the thickness of Nb-STO layers. The origin of the inversion of the MR is not clear, however we consider spin injection from ferromagnetic electrodes to Nb-STO through Schottky tunnel barriers plays an important role. © 2013 The Korean Physical Society.

    DOI

  • Epitaxial growth and physical properties of Heusler/perovskite heterostructures

    K. Kobayashi, K. Ueda, N. Fukatani, H. Kawada, K. Sakuma, H. Asano

    Journal of the Korean Physical Society   63 ( 3 ) 620 - 623  2013年08月  [査読有り]

     概要を見る

    Multiferroic heterostructures of the ferromagnetic, half-metallic Heusler Fe2CrSi (FCS) and the ferroelectric perovskite Ba0.7Sr0.3TiO3 (BSTO) have been formed by magnetron sputtering, and their magnetic and ferroelectric properties have been investigated. FCS/BSTO bilayer structures were epitaxially grown on LaAlO3 substrates with epitaxial relationships of FCS (001)[110]//BSTO (001)[100]. Multiferroic properties with a remanent polarization of 10.6 μC/cm2 and a saturation magnetization of 417 emu/cc were observed for the FCS/BSTO heterostructures at room temperature. These results suggest that the Heusler/perovskite epitaxial heterostructure is a promising candidate for fabricating multiferroic devices. © 2013 The Korean Physical Society.

    DOI

  • Preparation and properties of inverse perovskite Mn3GaN thin films and heterostructures

    H. Tashiro, R. Suzuki, T. Miyawaki, K. Ueda, H. Asano

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   63 ( 3 ) 299 - 301  2013年08月  [査読有り]

     概要を見る

    Thin films and heterostructures of Mn3GaN with an inverse perovskite structure were grown epitaxially on SrTiO3 (001) and (La0.18Sr0.82)(Al0.59Ta0.41)O-3 (001) (LSAT) substrates by ion beam sputtering, and their structural and electrical properties have been investigated. Mn3GaN epitaxial thin films showed metallic behavior of temperature-dependent resistivity with a small maximum at 290-340 K. The maximum resistivity could be attributed to the magnetic transition from antiferromagnetism to paramagnetism. It has been found that epitaxial heterostructures formed by ferroelectric Ba0.7Sr0.3TiO3 and Mn3GaN layers exhibit a large magnetocapacitance effect of more than 2000% in an applied magnetic filed of 1.5 T.

    DOI

  • The effect of magnetocrystalline anisotropy on the domain structure of patterned Fe2CrSi Heusler alloy thin films

    T. Miyawaki, M. Foerster, S. Finizio, C. A. F. Vaz, M. -A. Mawass, K. Inagaki, N. Fukatani, L. Le Guyader, F. Nolting, K. Ueda, H. Asano, M. Klaeui

    JOURNAL OF APPLIED PHYSICS   114 ( 7 ) 073905-1-5  2013年08月  [査読有り]

     概要を見る

    The effects of magnetic anisotropy on domain structures in half-metallic Heusler alloy Fe2CrSi thin film elements were investigated using high resolution x-ray magnetic circular dichroism photoemission electron microscopy. The transition of the dominating contribution from the magnetocrystalline anisotropy to the shape anisotropy is observed in square-shaped elements when reducing the size below 2.0-2.5 mu m. In particular, we identify in disk-shaped Heusler elements the vortex state as the ground state. The shape-anisotropy dominated, well-defined magnetization configuration shows the potential of the Fe2CrSi Heusler alloy for applications in vortex-core- or domain-wall-devices, where the high spin polarization is desirable. (C) 2013 AIP Publishing LLC.

    DOI

  • Ferromagnetic Schottky junctions using half-metallic Co2MnSi/diamond heterostructures

    K. Ueda, T. Soumiya, M. Nishiwaki, H. Asano

    APPLIED PHYSICS LETTERS   103 ( 5 ) 052408-1-4  2013年07月  [査読有り]

     概要を見る

    We demonstrate half-metallic Heusler Co2MnSi films epitaxially grown on diamond semiconductors using the ion-beam assisted sputtering method. Lower temperature growth below similar to 400 degrees C is key for obtaining abrupt Co2MnSi/diamond interfaces. The Co2MnSi films on diamond showed a negative anisotropic magnetoresistance of similar to 0.2% at 10 K, suggesting the half-metallic nature of the Co2MnSi films. Schottky junctions formed using the Co2MnSi/diamond heterostructures at 400 degrees C showed clear rectification properties with a rectification ratio of similar to 10(3). The Schottky barrier heights of the Co2MnSi/diamond interfaces were estimated to be similar to 0.8 eV. These results indicate that Co2MnSi is a promising spin source for spin injection into diamond. (C) 2013 AIP Publishing LLC.

    DOI

  • Growth and Properties of a-Axis Oriented Thin Films of Infinite-Layer Sr1-xLaxCuO2

    Hiroyuki Akatsuka, Keita Sakuma, Tetsuya Miyawaki, Kenji Ueda, Hidefumi Asano

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   23 ( 3 ) 7501204-1-4  2013年06月  [査読有り]

     概要を見る

    A-axis oriented, electron-doped, Sr1-xLaxCuO2 thin films were grown on LaAlO3 and YAlO3 substrates by magnetron sputtering. X-ray diffraction analysis revealed that in an as-grown state, the a-axis oriented films grew with the long-c phase, which is related to oxygen vacancies in the CuO2 planes, unlike the c-axis oriented films. Another feature of our a-axis oriented films is that the films contain 90 degrees rotated domains from in-plane X-ray diffraction and planer transmission electron microscopy image. We discuss features of a-axis oriented films in terms of oxygen vacancies in the CuO2 planes.

    DOI

  • Structural and magnetic properties in Heusler-type ferromagnet/ antiferromagnet bilayers

    N. Fukatani, K. Inagaki, T. Miyawaki, K. Ueda, H. Asano

    Journal of Applied Physics   113 ( 17 ) 17C103-1-3  2013年05月  [査読有り]

     概要を見る

    The structure and magnetic properties of Heusler ferromagnet/ antiferromagnet (FM/AFM) bilayers were investigated. Structural characterization revealed that Fe2CrSi/Ru2MnGe bilayers were epitaxially grown with an L21 ordered structure when the Ru2MnGe growth temperature was 573 K. The magnetization curve indicates that exchange bias occurs in the Fe2CrSi/Ru2MnGe bilayers at 77 K. The appearance of an exchange-anisotropy field Hex depends on the growth of Ru2MnGe layer, indicating that the exchange bias originates from the epitaxial Fe2CrSi/Ru2MnGe interface. The exchange anisotropy energy Jk of the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru2MnGe bilayer systems appears to follow a Heisenberg-like exchange coupling model. This suggests that the Cr and Mn interface atoms in the FM layers play significant roles in exchange coupling in the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru 2MnGe bilayer systems, respectively. © 2013 American Institute of Physics.

    DOI

  • High-temperature characteristics of Ag and Ni/diamond Schottky diodes

    K. Ueda, K. Kawamoto, T. Soumiya, H. Asano

    Diamond and Related Materials   38   41 - 44  2013年  [査読有り]

     概要を見る

    The high-temperature characteristics of diamond Schottky diodes fabricated using Ag or Ni on in-situ boron-doped diamond were examined. Up to 600 C, Ag Schottky diodes exhibited a high rectification ratio of the order of 10 4. Even at ∼ 750 C, their rectification ratio was about 10, indicating that diamond field effect transistors with Ag Schottky diodes can operate at this temperature. In contrast, Ni Schottky diodes did not show clear rectification above 600 C. An analysis of the I-V curves indicated that the Ag Schottky diodes have a higher rectification ratio than the Ni Schottky diodes at high temperatures due to their higher barrier heights (φB = ∼ 2.0 and ∼ 0.7 eV for Ag and Ni, respectively). © 2013 Elsevier B.V.

    DOI

  • Antiferromagnetic Heusler Ru-2 MnGe Epitaxial Thin Films Showing Neel Temperatures up to 353 K

    N. Fukatani, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    IEEE TRANSACTIONS ON MAGNETICS   48 ( 11 ) 3211 - 3214  2012年11月  [査読有り]

     概要を見る

    Structural and electrical transport properties were investigated for Heusler-type alloy Ru-2 MnGe thin films. Ru-2 MnGe films onMgO substrate were subjected to an in-plane compressive strain due to their small lattice mismatch (-0.7%), and exhibited enhanced antiferromagnetic transition temperature (T-N) up to 353 K, which is much higher than that of the bulk material (T-N = 316 K). In contrast, the films on MgAl2O4 were almost in a relaxed-strain state, and showed T-N close to the bulk value (304 K). It was also found that the T-N of Ru-2 MnGe thin films on MgO exhibited oscillating behavior depending on c/a ratio. We argued that the next-nearest neighbor magnetic interactions (J(2)) of Mn-Mn atoms has oscillated depending on the degree of strain in Ru-2 MnGe, which contribute to the oscillating behavior of T-N against c/a.

    DOI

  • Ferromagnetic Schottky junctions using diamond semiconductors

    K. Ueda, T. Soumiya, H. Asano

    DIAMOND AND RELATED MATERIALS   25   159 - 162  2012年05月  [査読有り]

     概要を見る

    Schottky junctions, formed using various ferromagnetic metals and alloys, were fabricated on hydrogen-terminated (H-terminated) diamond, and their interfacial characteristics were evaluated. A clear work function dependence of the Schottky barrier height (phi(B)) was obtained for these junctions, indicating that the Schottky barrier height between H-terminated diamond and ferromagnetic metals can be controlled by selecting metals with appropriate work functions. phi(B) for Ni and NiFe, which have higher work functions above 5 eV, is lower than phi(B) for other ferromagnetic metals. These results indicate that ferromagnetic metals with higher work function are promising for spin injection into diamond semiconductors. (C) 2012 Elsevier B.V. All rights reserved.

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  • Structural and electrical properties of half-Heusler La-Pt-Bi thin films grown by 3-source magnetron co-sputtering

    Tetsuya Miyawaki, Nozomi Sugimoto, Naoto Fukatani, Tatsuhiko Yoshihara, Kenji Ueda, Nobuo Tanaka, Hidefumi Asano

    JOURNAL OF APPLIED PHYSICS   111 ( 7 ) 07E327-1-3  2012年04月  [査読有り]

     概要を見る

    Half-Heusler La-Pt-Bi thin films have been deposited on YAlO3(001) substrate by 3-source magnetron co-sputtering. Control of the Bi content was the critical factor to obtain single phase, c-axis-oriented thin films. Generation of secondary phases was effectively prevented by precise control of the deposition rate for separate targets as well as adjustment of the deposition temperature. The realization of single-phase LaPtBi thin films will provide new potential applications to topological insulating devices based on Heusler alloys. (C) 2012 American Institute of Physics. [doi:10.1063/1.3675986]

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  • Fabrication of MgAl2O4 Thin Films on Ferromagnetic Heusler Alloy Fe2CrSi by Reactive Magnetron Sputtering

    Naoto Fukatani, Keima Inagaki, Kenichiro Mari, Hirohito Fujita, Tetsuta Miyawaki, Kenji Ueda, Hidefumi Asano

    JAPANESE JOURNAL OF APPLIED PHYSICS   51 ( 2 ) 02BM04-1-4  2012年02月  [査読有り]

     概要を見る

    Epitaxial MgAl2O4 thin films were grown on Heusler alloy Fe2CrSi by reactive magnetron sputtering of a MgAl2 target in an O-2+Ar atmosphere. To grow MgAl2O4 on Fe2CrSi, we inserted a protective layer of MgAl2 between Fe2CrSi and MgAl2O4 to prevent Fe2CrSi from being oxidized. Growth of MgAl2O4 was found to be very sensitive to the MgAl2 thickness and P-O2 during deposition of MgAl2O4. A strong XRD peak of MgAl2O4 (004) was observed with an ultrathin (0.2 nm) MgAl2 layer. The saturation magnetic moment of Fe2CrSi was measured to be 370 emu/cm(3) (1.84 mu B/f.u.) at room temperature and it is expected to have a high spin polarization. The Fe2CrSi/MgAl2O4 heterostructure is promising for use in future spintronic devices. (C) 2012 The Japan Society of Applied Physics

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  • Epitaxial thin films of ordered double perovskite SrLaVMoO6

    Katsutoshi Sanbou, Keita Sakuma, Tetsuya Miyawaki, Kenji Ueda, Hidefumi Asano

    Materials Research Society Symposium Proceedings   1454   21 - 26  2012年  [査読有り]

     概要を見る

    Epitaxial thin films of SrLaVMoO6 with an ordered double perovskite structure have been grown on (001) and (111) SrTiO3 substrates by magnetron sputtering. The optimized (111) film exhibited a clear (111) diffraction peak, which is a superlattice reflection of double perovskite unite cell, indicating clear B-site ordering. Temperature dependences of resistivity ρ show metallic behavior and transition point at 140-150 K, of which behavior is reminiscent of the electrical properties of materials showing long-range magnetic or antiferromagnetic order. XPS results of the Mo 3d core level spectra are discussed in terms of the B-site ordering and oxygen nonstoichiometry. © 2012 Materials Research Society.

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  • ダイヤモンド半導体を用いた強磁性ショットキー接合の作製

    宗宮嵩, 植田研二, 深谷直人, 宮脇哲也, 浅野秀文

    J. Magn. Soc. Jpn.   36   297-300  2012年  [査読有り]

  • ホイスラーペロブスカイト積層構造のマルチフェロイック特性

    小林耕平, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    J. Magn. Soc. Jpn.   36   213-216  2012年  [査読有り]

  • 逆ペロブスカイトMn3GaN薄膜の構造と電気特性

    田代裕樹, 宮脇哲也, 植田研二, 浅野秀文

    J. Magn. Soc. Jpn.   36   188-191  2012年  [査読有り]

  • 3元同時スパッタリング法によるLa-Pt-Bi薄膜の作製

    杉本望実, 深谷直人, 吉原健彦, 宮脇哲也, 植田研二, 田中信夫, 浅野秀文

    J. Magn. Soc. Jpn.,   36   179-182  2012年  [査読有り]

  • Inter-Layer Exchange Coupling in Fe2CrSi/Fe2VSi Multilayers Fabricated on MgAl2O4 Substrates

    Tetsuya Miyawaki, Kazunari Takahashi, Naoto Fukatani, Kenji Ueda, Hidefumi Asano

    IEEE TRANSACTIONS ON MAGNETICS   47 ( 10 ) 2643 - 2645  2011年10月  [査読有り]

     概要を見る

    In this study, we have fabricated Heusler alloy Fe2CrSi/Fe2VSi superlattice on MgAl2O4 substrate and have investigated interlayer exchange coupling among Fe2CrSi layers. Biquadratic coupling is dominated below the Neel temperature of Fe2VSi. By comparing magnetic coupling energy at 77 K and room temperature, it is suggested that the inter-layer exchange coupling is dominated by the proximity effect, i.e. the antiferromagnetic alignment of magnetic moments in Fe2VSi spacer layer.

    DOI

  • Magnetic and electronic properties of double perovskite Sr 2-xLaxVMoO6

    Hiroyuki Matsushima, Hirotaka Gotoh, Yoichi Takeda, Kenji Ueda, Hidefumi Asano

    Japanese Journal of Applied Physics   50 ( 10 ) 103004  2011年10月  [査読有り]

     概要を見る

    The magnetic and electronic properties of double perovskite Sr 2-xLaxVMoO6 (x = 0:9-1:2) polycrystalline bulk samples have been investigated. Magnetization and electrical resistivity measurements indicate that Sr2-xLaxVMoO6 is an antiferromagnetic metal with an antiferromagnetic transition temperature in the range 123-146 K. X-ray photoemission spectroscopy measurements reveal that Mo has a tetravalent state (Mo4+) and V has a trivalent state (V 3+) in SrLaVMoO6. These results indicate that V 3+ (3d2) ions are antiferromagnetically coupled with Mo4+ (4d2) ions. Electron-doping effects of Sr 2+xLaxVMoO6 by La substitution differed from those of half-metallic Sr2-xLaxFeMoO6. This can be qualitatively explained by considering the different electron-doped orbitals and ordering ratios of B-site ions between Sr2-xLa xVMoO6 and Sr2-xLaxFeMoO6 (Mo/V or Mo/Fe). © 2011 The Japan Society of Applied Physics.

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  • Epitaxial strain and antiferromagnetism in Heusler Fe2VSi thin films

    N. Fukatani, K. Ueda, H. Asano

    JOURNAL OF APPLIED PHYSICS   109 ( 7 ) 073911  2011年04月  [査読有り]

     概要を見る

    The effects of biaxial strain on the electrical and magnetic properties of an antiferromagnetic Heusler compound Fe2VSi were systematically investigated. A series of epitaxial Fe2VSi thin films on MgAl2O4 and MgO substrates were fabricated with different tensile strains by varying the substrate-lattice mismatch and the film thickness. The strain was characterized by the ratio of the out-of-plane lattice parameter c to the in-plane lattice parameter a; this ratio c/a varied from 0.987 to 0.998 at room temperature. The tensile epitaxial strain was found to increase the antiferromagnetic Neel temperature T-N to 193 K, which is 70 K higher than that for the unstrained bulk material. A clear dependence of T-N on c/a was observed, which is consistent with theoretical predictions in which the band Jahn-Teller effect plays a significant role. (C) 2011 American Institute of Physics. [doi:10.1063/1.3555089]

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  • Fabrication and physical properties of double perovskite SrLaVMoO6 thin films

    H. Matsushima, H. Gotoh, T. Miyawaki, K. Ueda, H. Asano

    JOURNAL OF APPLIED PHYSICS   109 ( 7 ) 07E321.  2011年04月  [査読有り]

     概要を見る

    SrLaVMoO6 thin films have been grown on various substrates by magnetron sputtering in Ar+H-2 mixture gas. High-quality c-axis oriented SrLaVMoO6 films have been obtained in the growth temperature of 630 degrees C and Ar + 5% H-2 mixture gas. The SrLaVMoO6 films showed low resistive metallic behavior, which is comparable to bulk SrLaVMoO6. X-ray photoemission spectroscopy measurements indicate that the dominant valence state for Mo and V in the SrLaVMoO6 films is tetravalent (Mo4+) and trivalent state (V3+), respectively. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556898]

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  • MgAl2O4基板上に成長した格子整合系ホイスラー合金人工格子の結晶構造と磁気特性の相関

    宮脇哲也, 高橋一成, 深谷直人, 植田研二, 浅野秀文

    電子情報通信学会技術研究報告. MR, 磁気記録   110 ( 2011-03-04 ) 27-31  2011年

  • CoFe2O4/Ba0.7Sr0.3TiO3複合構造のマルチフェロイック特性

    田代裕樹, 小林耕平, 小林智, 宮脇哲也, 植田研二, 浅野秀文

    電子情報通信学会技術研究報告. MR, 磁気記録   110 ( 2011-03-04 ) 33-38  2011年

  • Fe2VSi薄膜の歪み効果と電気伝導特性

    深谷直人, 植田研二, 浅野秀文

    J. Magn. Soc. Jpn.   35   260-263  2011年  [査読有り]

  • La0.7Sr0.3MnO3/Bi1-xBaxFeO3接合におけるスピンフィルター効果

    小林 智, 立木 翔治, 吉本 耕助, 杉本 靖典, 竹田 陽一, 植田 研二, 浅野 秀文

    J. Magn. Soc. Jpn.   34   499-502  2010年05月  [査読有り]

  • MgAl2O4基板上のホイスラー合金薄膜・人工格子の構造と磁性

    竹田陽一, 深谷直人, 高橋一成, 藤田裕人, 植田研二, 浅野秀文

    IEICE Technical Report   MR2009-66   45-51  2010年03月  [査読有り]

  • 格子歪みによるFe2VSi薄膜の反強磁性の安定化

    深谷 直人, 竹田 陽一, 植田 研二, 浅野 秀文

    J. Magn. Soc. Jpn.   34   307-310  2010年03月  [査読有り]

  • High Temperature Operation of Boron-Implanted Diamond Field-Effect Transistors

    Kenji Ueda, Makoto Kasu

    JAPANESE JOURNAL OF APPLIED PHYSICS   49 ( 4 ) 04DF16-1-4  2010年  [査読有り]

     概要を見る

    Diamond field effect transistors (FETs) with Pt or Al Schottky gate electrodes were fabricated on high-quality boron (B)-implanted layers formed by combining ion-implantation and high-pressure and high-temperature annealing. The high temperature characteristics of these FETs were examined. Pt-gate B-implanted diamond FETs showed maximum drain current (I-DS) of 0.16 mA/mm at gate voltage of -2 V and drain voltage of -20 V at 25 degrees C. The I-DS increased as temperature increased because of the activation of boron, and it showed maximum value of 3.9 mA/mm at similar to 200 degrees C. Al-gate FETs showed similar temperature dependence of I-DS, though the operation temperature and I-DS were higher than those of Pt-gate FETs. High-temperature operation of the B-implanted diamond FETs was possible above 550 degrees C without severe drain bulk leakage, though the maximum I-DS gradually decreased as temperature increased because of drain bulk leakage above 300 degrees C. (C) 2010 The Japan Society of Applied Physics

    DOI

  • 反強磁性体SrLaVMoO6の構造とスピン分極率

    松島 宏行, 後藤 大尚, J.Zhong, 竹田 陽一, 植田 研二, 浅野 秀文, A. Rajanikanth, 宝野 和博

    J. Magn. Soc. Jpn.   34   1-4  2009年11月  [査読有り]

  • Structural and electrical properties of H-terminated diamond field-effect transistor

    Michal Kubovic, Makoto Kasu, Yoshiharu Yamauchi, Kenji Ueda, Hiroyuki Kageshima

    DIAMOND AND RELATED MATERIALS   18 ( 5-8 ) 796 - 799  2009年05月  [査読有り]

     概要を見る

    A dielectric barrier separating hydrogen induced p-type channel and Al gate metal contact of diamond FET has been investigated. The separation barrier is necessary to prevent tunneling current between the H-induced channel and the gate contact. In this investigation, CV measurements, fitting of forward IV characteristics, TEM and SIMS profiles have been used to obtain a more detailed picture of this barrier layer. While the composition of this layer is not clear, TEM and SIMS measurements indicate that this layer may be connected to a diamond phase or aluminium oxide. Using material properties of these materials, thickness of the separation layer extracted from the CV measurements was between 5-10 nm and the channel sheet change density was above 1 x 10(13) cm(-2). This thickness is in good agreement with the TEM observations. Frequency dependent CV measurements showed almost no frequency dependence, and no UV light dependence has been observed. Temperature dependent CV measurements showed a decrease of the dielectric constant at 100 degrees C. Fitting of the forward tunnelling current indicated a thickness of the barrier layer of about 5 nm with a barrier height of 2.4 eV. (C) 2009 Elsevier B.V. All rights reserved.

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  • Beryllium-doped single-crystal diamond grown by microwave plasma CVD

    K. Ueda, M. Kasu

    DIAMOND AND RELATED MATERIALS   18 ( 2-3 ) 121 - 123  2009年02月  [査読有り]

     概要を見る

    We performed beryllium (Be) doping to diamond by inserting a solid Be-rod into the plasma ball during microwave plasma CVD growth. The Be concentration can be controlled in the range from similar to 10(16) to similar to 10(18) cm(-3) by changing the Be-rod insertion depth in the plasma ball and the microwave power. In cathodoluminescence (CL) spectra of Be-doped CVD films, we observed a peak at 4.760 eV and its phonon replica as well as free-exciton (FE)related emissions. Peak energies of these emissions are close to those of Be-related emissions from Be-implanted diamond films. (C) 2008 Elsevier B.V. All rights reserved.

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  • 水素終端ダイヤモンド高周波電力FETの現状と課題

    嘉数, 植田, Kubovic

    ニューダイヤモンド   25 ( 1 ) 3  2009年

  • High-pressure and high-temperature annealing of diamond ion-implanted with various elements

    K. Ueda, A. Kasu

    DIAMOND AND RELATED MATERIALS   17 ( 7-10 ) 1269 - 1272  2008年07月  [査読有り]

     概要を見る

    We tried to dope various ions (B, Al, Ga, Mg, and Be) into diamond films by combining ion-implantation and high-pressure and high-temperature annealing. In cathodoluminescence spectra of Be-implanted films, previously unreported emissions appeared at 4.843, 4.687, 4.533 eV. These emissions were only observed from Be-implanted films, and they were not observed from B, Al, Ga, and Mg-implanted ones. The 4.843-eV line is assigned to zero phonon line, and the 4.687- and 4.533-eV lines are its phonon replicas because the energy difference between each peak is close to the optical phonon energy of diamond (similar to 0.15 eV). The temperature dependence of the 4.843-eV line is similar to that of bound excitons. (C) 2008 Elsevier B.V. All rights reserved.

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  • RF equivalent-circuit analysis of p-type diamond field-effect transistors with hydrogen surface termination

    Makoto Kasu, Kenji Ueda, Hiroyuki Kageshima, Yoshiharu Yamauchi

    IEICE TRANSACTIONS ON ELECTRONICS   E91C ( 7 ) 1042 - 1049  2008年07月  [査読有り]

     概要を見る

    On the basis of the RF characteristics of p-type diamond field-effect transistors (FETs) with hydrogen surface termination, we establish an equivalent circuit (EQC) model. From comparisons of three cases we reveal that to represent the device performance in the EQC, the source, gate, and drain resistance should be considered but that the gate-source and gate-drain resistance can be ignored. The features of diamond FETs are (1) a plateau of the gate capacitance in a certain gate voltage range. (2) maximum f(T) and f(MAX) cut-off frequencies near the threshold gate voltage, and (3) a high f(MAX)/f(T) ratio similar to 3.8. We discuss these features in terms of the energy barrier between the gate metal and the two-dimensional hole channel and drift region below the gate.

    DOI

  • Gate interfacial layer in hydrogen-terminated diamond field-effect transistors

    Makoto Kasu, Kenji Ueda, Hiroyuki Kageshima, Yoshiharu Yamauchi

    DIAMOND AND RELATED MATERIALS   17 ( 4-5 ) 741 - 744  2008年04月  [査読有り]

     概要を見る

    Cross-sectional transmission microscopy images of hydrogen-terminated diamond field-effect transistor reveal interfacial layers between the metal and hydrogen-terminated diamond layer. Especially interesting is that an interfacial layer between Al and H-terminated diamond is clearly seen. This layer corresponds to the energy barrier, which we confirmed from an RF analysis of a diamond FET. During growth, an amorphous-like subsurface layer with vacancies has already formed on H-terminated diamond, and during subsequent metal evaporation, metal diffuses through vacancies into the subsurface layer, and eventually the interfacial layer forms. (C) 2008 Elsevier B.V. All rights reserved.

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  • High-pressure and high-temperature annealing effects of boron-implanted diamond

    K. Ueda, M. Kasu

    DIAMOND AND RELATED MATERIALS   17 ( 4-5 ) 502 - 505  2008年04月  [査読有り]

     概要を見る

    We show that high-pressure and high-temperature (HPHT) annealing of ion-implanted diamond is efficient as a doping technique. The HPHT annealing condition is located in the thermodynamically stable region for diamond. The HPHT annealing is highly effective for the recovery of damage induced by ion implantation. In the entire annealing temperature range, the HPHT annealing is more efficient than conventional thermal annealing methods such as vacuum annealing. At 1400 degrees C, we obtained the highest boron doping efficiency of 7.1%, which is ten times higher than that by vacuum annealing. (C) 2007 Elsevier B.V. All rights reserved.

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  • Thick diamond layers angled by polishing to reveal defect and impurity depth profiles

    A. Tallaire, M. Kasu, K. Ueda

    DIAMOND AND RELATED MATERIALS   17 ( 4-5 ) 506 - 510  2008年04月  [査読有り]

     概要を見る

    Diamond layers were grown top a thickness of 25 to 35 mu m either on type-Ib synthetic or type-IIa natural diamond substrates by using high or low microwave-power densities. To evaluate defects and impurities depth profiles, the samples were angled by polishing and characterized by cathodoluminescence. The first important finding is that boron, nitrogen and structural defects seem to be concentrated in a 7-10-mu m-thick region near the substrate/layer interface, as evidenced by strong defect or impurity-related luminescences and a weak free-exciton peak. The diamond quality is thus much improved in the bulk or near the surface, especially when high microwave-power densities are used, due to the inhibition of unepitaxial crystals formation. The second important finding is that using type-IIa natural substrates, which contain extremely low levels of impurities, results in a strong decrease in the amount of boron and the intensity of the nitrogen-related peak both in the bulk and at the interface of the CVD layer. These results suggest that most impurities in our CVD layers could originate from the substrate itself (C) 2008 Elsevier B.V. All rights reserved.

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  • Origin of growth defects in CVD diamond epitaxial films

    A. Tallaire, M. Kasu, K. Ueda, I. Makimoto

    DIAMOND AND RELATED MATERIALS   17 ( 1 ) 60 - 65  2008年01月  [査読有り]

     概要を見る

    Three types of growth defects commonly found epitaxial diamond films grown by chemical vapour deposition (CVD), namely unepitaxial crystals (UCs), hillocks with flat top (FHs) and pyramidal hillocks (PHs), were etched using hydrogen/oxygcn plasma to discuss their origin. UCs formed at random locations on the grown layer without any apparent relation with the substrate. Their nucleation might be due to contaminants and their development controlled by the growth conditions in the plasma. In contrast, dislocations formed from impurities segregated at the interface between the substrate and the CVD layer, were found to be the origin of the FHs and the PHs. A simple crystal model that involves micro-faceting or twinning at an intrinsic stacking fault originating from the dislocation core is proposed to explain the formation and the evolution of the growth defects. (C) 2007 Elsevier B.V. All rights reserved.

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  • Diamond FETs on boron-implanted and high-pressure and high-temperature annealed homoepitaxial diamond

    Kenji Ueda, Yoshiharu Yamauchi, Makoto Kasu

    PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 9   5 ( 9 ) 3175 - 3177  2008年  [査読有り]

     概要を見る

    By combining ion-implantation and high-pressure and high-temperature (HPHT) annealing, we have obtained boron implanted diamond layers with a high a hole concentration and mobility and succeeded in fabricating diamond FETs using the B-implanted layers. For a B dose of 3 x 10(15) cm(-2), as heet hole concentration and mobility of 1.6 x 10(13) cm(-2) and 41 cm(2)/Vs at 300 K were obtained. Diamond FETs fabricated on the B-implanted layer showed maximum drain current of 0.15 mA/mm at gate voltage of -2 V and maximum break-down voltage of 530 V, corresponding to similar to 1.1 MV/cm. The breakdown voltage value is comparable to those of Schottky diodes using B-doped CVD diamond films. These results confirm the high quality of the B-implanted and HPHT-annealed layers. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Diamond RF FETs and other approaches to electronics

    Makoto Kasu, Kenji Ueda, Hiroyuki Kageshima, Yoshitaka Taniyasu

    PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 9   5 ( 9 ) 3165 - 3168  2008年  [査読有り]

     概要を見る

    Diamond semiconductor possesses exceptional physical properties, such as high thermal conductivity, high breakdown field, and high mobility, and is therefore expected to offer the highest performance, among semiconductors as high-frequency, high-power transistors. At present the most critical issue in achieving diamond transistors is the lack of an n-type or p-type dopant with low activation energy. This paper reviews approaches towards electronic-device application of diamond done mainly by NTT Basic Research Laboratories. First it describes our diamond field-effect transistors with 0.1-mu m gate length, which exhibit high cut-off frequencies for the current and power gains, f(T) and f(MAX), of 45 GHz and of 120 GHz, and output power density of 2.1 W/mm at 1 GHz. Next it shows how doping efficiency in ion implantation can be improved by using high-pressure high-temperature annealing. Finally, it describes Our concept of diamond/nitride heterostructure and presents results that confirm its feasibility. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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  • 水素終端ダイヤモンドFETのゲート金属界面

    嘉数, 植田, 影島

    表面科学   29   159-163  2008年

  • Interface microstructure of MgB2/Al-AlOxMgB2 Josephson junctions studied by cross-sectional transmission electron microscopy

    Kenji Ueda, Shiro Saito, Kouichi Semba, Toshiki Makimoto, Michio Naito

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS   46 ( 12-16 ) L271 - L273  2007年04月  [査読有り]

     概要を見る

    We investigated the interface microstructure of sandwich-type MgB2/Al-A1O(x)/MgB2 Josephson tunnel junctions by cross-sectional transmission electron microscopy (TEM) in order to clarify the non-idealities in the junction characteristics. The results indicate that there are poor-crystal line MgB2 layers and/or amorphous Mg-B composite layers of a few nanometers between the AlOx barrier and upper MgB2 layer. The poor-crystalline upper Mg-B layers seem to behave as normal metal or deteriorated superconducting layers, which may be the principal reason for all non-idealities of our MgB2/Al-AIO(x)/MgB2 junctions.

    DOI

  • Diamond-based RF power transistors: Fundamentals and applications

    M. Kasu, K. Ueda, Y. Yamauchi, A. Tallaire, T. Makimoto

    DIAMOND AND RELATED MATERIALS   16 ( 4-7 ) 1010 - 1015  2007年04月  [査読有り]

     概要を見る

    The present status of diamond-based transistors for high-frequency and high-power applications is reviewed. We have achieved the drain current density of 550 mA/mm, cut-off frequencies for current gain (f(T)) and power gain (f(MAX)) of 45 GHz and 120 GHz, respectively, and output-power density of 2.1 W/mm at 1 GHz in class-A operation of a field-effect transistor (FET) with hydrogen (H)-surface-terminated diamond. We have found that gate capacitance can be separated into depletion-layer capacitance and insulator capacitance. Concerning a stability of H-surface termination, no apparent decrease in the current for an FET without a gate contact was observed, but gate bias stress results in a slight decrease in the drain current and simultaneously an increase in the gate leakage current. (c) 2007 Elsevier B.V. All rights reserved.

    DOI

  • High-pressure and high-temperature annealing as an activation method for ion-implanted dopants in diamond

    K. Ueda, M. Kasu, T. Makimoto

    APPLIED PHYSICS LETTERS   90 ( 12 ) 122102-1-3  2007年03月  [査読有り]

     概要を見る

    The authors show that high-pressure and high-temperature (HPHT) annealing is very effective for the activation of ion-implanted dopants in diamond. The HPHT annealing condition is located in the thermodynamically stable region for diamond in the phase diagram and is, therefore, much more efficient for the recovery of implantation-induced damage and for the activation of ion-implanted dopants than thermal annealing in vacuum. The B-implanted film after HPHT annealing showed a high mobility of 632 cm(2)/V s with a sheet hole concentration of 4.8x10(10) cm(-2) at 300 K and the doping efficiency of similar to 7%. The mobility is the highest so far for ion-implanted diamond. In the entire annealing temperature range, the HPHT annealing is more efficient than the thermal annealing in vacuum. (c) 2007 American Institute of Physics.

    DOI

  • Terahertz mixing in MgB2 microbolometers

    S. Cherednichenko, V. Drakinskiy, K. Ueda, M. Naito

    APPLIED PHYSICS LETTERS   90 ( 2 ) 023507-1-3  2007年01月  [査読有り]

     概要を見る

    The authors report on a terahertz (600 GHz) mixing experiment with MgB2 microbolometers in the resistive state. The authors observed that for a 20 nm film a mixer gain bandwidth of 2.3 GHz can be achieved, corresponding to an energy relaxation time of 70 ps. The experimental results were analyzed using a two-temperature model. As a result, the phonon escape time of similar to 20 ps was deduced. At 1.6 THz the MgB2 mixer uncorrected noise temperature was 11 000 K. The obtained results show that MgB2 bolometers are good prospects for the terahertz range as both broadband mixers and fast direct detectors.

    DOI

  • Gate capacitance-voltage characteristics of submicron-long-gate diamond field-effect transistors with hydrogen surface termination

    M. Kasu, K. Ueda, Y. Yamauchi, T. Makimoto

    APPLIED PHYSICS LETTERS   90 ( 4 ) 043509-1-3  2007年01月  [査読有り]

     概要を見る

    The radio-frequency characteristics of p-type diamond field-effect transistors with hydrogen surface termination were numerically analyzed using an equivalent-circuit model. From the gate-source capacitance (C-GS)-voltage (V-GS) results extracted from measured s parameters, the authors found a plateau in C-GS within a certain V-GS range. This means that a two-dimensional hole gas channel forms parallel to the surface and that the channel is separated by a thin energy-barrier layer with an infinite height from the gate metal. At a high negative V-GS, as negative V-GS is increased, C-GS increases steeply. This results from holes penetrating the energy barrier. (c) 2007 American Institute of Physics.

    DOI

  • High-pressure and high-temperature annealing effects on CVD homoepitaxial diamond films

    K. Ueda, M. Kasu, A. Tallaire, T. Makimoto

    DIAMOND AND RELATED MATERIALS   15 ( 11-12 ) 1789 - 1791  2006年11月  [査読有り]

     概要を見る

    High-pressure and high-temperature (HPHT) annealing effects on the chemical vapor-deposited (CVD) homoepitaxial diamond films were investigated. By the HPHT annealing, the intensity of free-exciton (FE)-related emission was increased by - 2 times and the luminescence bands from 270 to 320 min, which originate from 5RL and 2BD bands, were almost completely eliminated in the cathodoluminescence (CL) spectrum. The CL intensity of band-A emission, which is related to crystal defects in diamond, was also decreased. The hole mobility at room temperature was increased from 826 to 1030 cm(2)/Vs by HPHT annealing. These results suggest that HPHT annealing decreases the crystalline defects and improves the optical and electronic properties of homoepitaxial diamond films. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Characterization of high-quality polycrystalline diamond and its high FET performance

    K. Ueda, M. Kasu, Y. Yamauchi, T. Makimoto, M. Schwitters, D. J. Twitchen, G. A. Scarsbrook, S. E. Coe

    DIAMOND AND RELATED MATERIALS   15 ( 11-12 ) 1954 - 1957  2006年11月  [査読有り]

     概要を見る

    We characterized high-quality polycrystalline diamond with large grains and fabricated polycrystalline diamond field effect transistors (FETs). The polycrystalline diamond had (110) preferred orientation, and its typical grain size was similar to 100 mu m. Well-resolved free exciton related emissions were observed at room temperature in cathodoluminescence. The FETs showed extremely high DC and RF performance. The cut-off frequency for current gain (f(T)) and power gain (f(max)) were 45 and 120 GHz, respectively. The maximum drain current (I-DS) was 550 mA/mm. These values are the highest among diamond FETs, including those fabricated from single-crystal diamond. These results suggest that high-quality polycrystalline diamond, whose maximum size is 4 in., is very promising for diamond electronic devices. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Low-temperature growth of MgB2 thin films with T-c above 38 K

    Kenji Ueda, Toshiki Makimoto

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   45 ( 7 ) 5738 - 5741  2006年07月  [査読有り]

     概要を見る

    MgB2 thin films with the T-c above 38 K have been fabricated using molecular beam epitaxy (NIBE) at the growth temperature below 300 degrees C. The T-c of 38.2 K was obtained in 1.3-mu m-thick MgB2 films formed on SiC substrates with AIN buffer layers. The T-c is comparable to those of MgB2 single crystals and the highest among MgB2 films fabricated below 500 degrees C. Increase of the film thickness of MgB2 above 1 mu m was the key point to obtain high-quality films at low growth temperature.

    DOI

  • Diamond FET using high-quality polycrystalline diamond with f(T) of 45 GHz and f(max) of 120 GHz

    K. Ueda, M. Kasu, Y. Yamauchi, T. Makimoto, M. Schwitters, D. J. Twitchen, G. A. Scarsbrook, S. E. Coe

    IEEE ELECTRON DEVICE LETTERS   27 ( 7 ) 570 - 572  2006年07月  [査読有り]

     概要を見る

    Using high-quality polycrystalline chemical-vapor-deposited diamond films with large grains (similar to 100 mu m), field effect transistors (FETs) with gate lengths of 0.1 mu m were fabricated. From the RF characteristics, the maximum transition frequency f(T) and the maximum frequency of oscillation f(max) were similar to 45 and similar to 120 GHz, respectively. The fT and f(max) values are much higher than the highest values for single-crystalline diamond FETs. The dc characteristics of the FET showed a drain-current density-I-DS of 550 mA/mm at gate-source voltage V-GS of -3.5 V and a maximum transconductance g(m) of 143 mS/mm at drain voltage V-DS of -8 V. These results indicate that the high-quality polycrystalline diamond film, whose maximum size is 4 in at present, is a most promising substrate for diamond electronic devices.

    DOI

  • RF performance of diamond metel-semiconductor field-effect transistor at elevated temperatures and analysis of its equivalent circuit

    Haitao Ye, Makoto Kasu, Kenji Ueda, Yoshiharu Yamauchi, Narihiko Maeda, Satoshi Sasaki, Toshiki Makimoto

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   45 ( 4B ) 3609 - 3613  2006年04月  [査読有り]

     概要を見る

    Temperature dependent DC and RF characteristics of p-type diamond metal-semiconductor field-effect transistors (MESFETs) on hydrogen-terminated surfaces are investigated. The device is thermally stable up to 100 degrees C. because it does not deteriorate at all at higher temperatures. Temperature coefficients of transconductance (g(m)), drain conductance (g(ds)), gate-source capacitance (C-gs), gate-drain capacitance (C-gd), cut-off frequency (f(T)), and maximum drain current (I-ds) were obtained from small-signal equivalent circuit analysis. The cut-off frequency (fT) is almost totally independent of temperature. Intrinsic g(m), g(ds), and C-gs decrease with increasing temperature. C-gd is almost totally independent of temperature. The threshold voltage shifts to the negative side with increasing temperature. We propose a band model of an Al-gate contact/H-terminated diamond to explain the temperature dependence of these components.

    DOI

  • High RF output power for H-terminated diamond FETs

    M. Kasu, K. Ueda, H. Ye, Y. Yamauchi, S. Sasaki, T. Makimoto

    DIAMOND AND RELATED MATERIALS   15 ( 4-8 ) 783 - 786  2006年04月  [査読有り]

     概要を見る

    We report great improvement of RF output power for H-terminated diamond field-effect transistors (FETs). For the FET device with a gate width of 1 mm and a gate length of 0.4 mu m, the maximum output power (P-out) is 1.26 W, the maximum power gain is 23.2 dB, and the power added efficiency (PAE) is 56.3%. The increase in the device temperature when output power is 0.84 W is only similar to 0.6 degrees C. This is due to diamond having the highest thermal conductivity. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Temperature dependent DC and RF performance of diamond MESFET

    H. Ye, M. Kasu, K. Ueda, Y. Yamauchi, N. Maeda, S. Sasaki, T. Makimoto

    DIAMOND AND RELATED MATERIALS   15 ( 4-8 ) 787 - 791  2006年04月  [査読有り]

     概要を見る

    This paper reports the first Studies on temperature dependent DC and RF characteristics of diamond metal-semi conductor field-effect transistors along with circular-transmission-like-method measurements on hydrogen-terminated diamond surface. In general, the device under study is thermally stable up to 100 degrees C as it does not deteriorate at higher temperatures with the cut-off frequency for current gain maintained at 8 similar to 9 GHz. It is found that the sheet resistance is almost totally independent of temperature, contact resistance is negligible, and channel conductance underneath the gate decreases with increasing temperature. The threshold voltage for the device is found to shift to the negative side with increasing temperature. A small-signal equivalent circuit analysis reveals that both transconductance and gate-source capacitance decrease with increasing temperature,. which results in the almost constant cut-off frequency for current gain. The experimental results call be explained by the fact that with increasing temperature, the band near the Al/H-terminated diamond surface bends upward more weakly, which leads to a decrease of buffer capacitance. At the same time the mobility decreases and the transconductance therefore decreases. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • RF performance of diamond MESFET at elevated temperatures and its equivalent circuit

    H. Ye, M. Kasu, K. Ueda, Y. Yamauchi, N. Maeda, S. Sasaki, T. Makimoto

    Jpn. J. Appl. Phys.   45   3609-3613  2006年  [査読有り]

  • 2W/mm output power density at 1 GHz for diamond FETs

    M Kasu, K Ueda, H Ye, Y Yamauchi, S Sasaki, T Makitnoto

    ELECTRONICS LETTERS   41 ( 22 ) 1249 - 1250  2005年10月  [査読有り]

     概要を見る

    Great improvement in the output power density of diamond FETs on a diamond homoepitaxial layer grown using a high-purity source gas is reported. For a device with a gate length of 0.1 mu m and gate width of 100 pro, at 1 GHz, maximum output power density of 2.1 W/mm, maximum power gain of 10.9 dB, and power added efficiency of 31.8% were obtained.

    DOI

  • All-MgB2 Josephson tunnel junctions

    K Ueda, S Saito, K Sernba, T Makimoto, M Naito

    APPLIED PHYSICS LETTERS   86 ( 17 ) 172502-1-3  2005年04月  [査読有り]

     概要を見る

    Sandwich-type all-MgB2 Josephson tunnel junctions (MgB2/AlOx/MgB2) have been fabricated with as-grown MgB2 films formed by molecular-beam epitaxy. The junctions exhibit substantial superconducting current (IcRN product similar to 0.8 mV at 4.2 K), a well-defined superconducting gap (Delta = 2.2-2.3 mV), and clear Fraunhofer patterns. The superconducting gap voltage of Delta agrees well with the smaller gap in the multigap scenario. The results demonstrate that MgB2 has great promise for superconducting electronics that can be operated at T similar to 20 K. (c) 2005 American Institute of Physics.

    DOI

  • Prospects and problems in fabrication of MgB2 Josephson junctions

    K Ueda, M Naito

    IEICE TRANSACTIONS ON ELECTRONICS   E88C ( 2 ) 226 - 231  2005年02月  [査読有り]  [招待有り]

     概要を見る

    We briefly survey recent developments in the thin film synthesis and junction fabrication of MgB2 toward superconducting electronics. The most serious problem in the thin film synthesis of MgB2 is the high vapor pressure required for phase stability. This problem makes in-situ film growth difficult. However, there has been substantial progress in thin film technology for MgB2 in the past three years. The low-temperature thin-film process in a UHV chamber can produce high-quality MgB2 films with T-c similar to 35 K. Furthermore, technology to produce single-crystal epitaxial MgB2 films has recently been developed by using hybrid physical-chemical vapor deposition. With regard to Josephson junctions, various types of junctions have been fabricated, all of which indicate that MgB2 has potential for superconducting devices that operate at 20-30 K, the temperature reached by current commercial cryocoolers.

  • Tunnel junctions on as-grown MgB2 thin films

    K. Ueda, M. Naito

    Physica C   408-410   134-135  2004年  [査読有り]

  • MgB2 thin films for superconducting electronics

    M. Naito, K. Ueda

    Superconductor Sci. Tech.   17   R1-R18  2004年  [査読有り]

  • Tunnel junctions on as-grown superconducting MgB2 thin films

    K. Ueda, M. Naito

    IEEE trans. Appl. Superconductivity   13   3249-3252  2003年  [査読有り]

  • In-situ growth of superconducting MgB2 thin films by molecular beam epitaxy

    K. Ueda, M. Naito

    J. Appl. Phys.   93   2113-2120  2003年  [査読有り]

  • Synthesis and photoemission study of as-grown superconducting MgB2 thin films

    K Ueda, H Yamamoto, M Naito

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   378   225 - 228  2002年10月  [査読有り]

     概要を見る

    As-grown superconducting thin films of MgB2 were prepared by molecular beam epitaxy (MBE), and studied by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS). Only films prepared at temperatures between 150 and 320 degreesC showed superconductivity. The best T-c(onset) of 36 K was obtained with a sharp transition width of similar to1 K although the film crystallinity was poor. The in situ photoelectron spectra obtained on the surfaces of the MBE grown MgB2 films were free from dirt peaks. The XP spectra revealed the binding energy of the Mg 2p levels in MgB2 is close to that of metallic Mg and the binding energy of B 1s is close to that of transition-metal diborides. The valence UP spectra showed a clear Fermi edge although the density of states at E-F is low and the major components of the valence band are located between 5 and 11 eV. (C) 2002 Elsevier Science B.V. All rights reserved.

  • Superconducting thin films of electron-doped infinite-layer Sr1-xLaxCuO2 grown by molecular beam epitaxy

    S Karimoto, K Ueda, M Naito, T Imai

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   378   127 - 130  2002年10月  [査読有り]

     概要を見る

    We grew single-crystalline Sr1-xLaxCuO2 thin films of electron-doped infinite-layer compounds by molecular beam epitaxy. Crucial to our success was the use of KTaO3 substrates. The best film showed T-c(onset) = 41.5 K and T-c(zero) = 39.0 K. The resistivity of the optimum-doped films exhibited metallic temperature dependence with a low resistivity of 320 muOmega cm. at room temperature and 120 muOmega cm. just above T-c. Such excellent electrical properties have not previously been reported for this system with either thin films or bulk polycrystalline specimens. (C) 2002 Elsevier Science B.V. All rights reserved.

  • Single-crystalline superconducting thin films of electron-doped infinite-layer compounds grown by molecular-beam epitaxy

    S Karimoto, K Ueda, M Naito, T Imai

    APPLIED PHYSICS LETTERS   79 ( 17 ) 2767 - 2769  2001年10月  [査読有り]

     概要を見る

    Single-crystalline Sr1-xLaxCuO2 thin films of electron-doped infinite-layer compounds were grown by molecular-beam epitaxy. Crucial to our success was the use of KTaO3 substrates. The best film showed T-c(onset)=41.5 K and T-c(zero)=39.0 K, which is close to the highest T-c(onset) of 43 K for the bulk value. The resistivity of the optimum-doped film exhibited metallic temperature dependence with a low resistivity of 320 mu Omega cm at room temperature and 120 mu Omega cm just above T-c. (C) 2001 American Institute of Physics.

  • As-grown superconducting MgB2 thin films prepared by molecular beam epitaxy

    K Ueda, M Naito

    APPLIED PHYSICS LETTERS   79 ( 13 ) 2046 - 2048  2001年09月  [査読有り]

     概要を見る

    Superconducting thin films of magnesium diboride (MgB2) were prepared on various substrates [SrTiO3 (001), sapphire R, sapphire C and Si (111)] by molecular beam epitaxy. The growth temperature was examined in the ambient to 650 degreesC. Only films formed at temperatures between 150 and 320 degreesC showed superconductivity. The best T-C(onset) of 36 K with a sharp transition width of similar to1 K was observed. The T-C of the as-grown superconducting MgB2 thin films is close to the bulk value. (C) 2001 American Institute of Physics.

  • Fabrication of the low-resistive p-type ZnO by codoping method

    M Joseph, H Tabata, H Saeki, K Ueda, T Kawai

    PHYSICA B   302   140 - 148  2001年08月  [査読有り]

     概要を見る

    We have demonstrated the possibility of growing p-type ZnO films by a pulsed laser deposition technique combined with plasma gas source. The p-type ZnO film has been fabricated by passing N2O gas through an electron cyclotron resonance (ECR) or RF plasma source. N-O gas is effective to prevent "O" vacancy from occurring and introduce "N" as an acceptor, at the same time. With Ca and N codoping technique, we have observed a room temperature resistivity of 0.5 Omega cm and a carrier concentration of 5 x 10(19)cm (3) in ZnO film on glass substrate. Two-step growth, with a thin ZnO template layer formed at high temperature, is quite effective to realize a well crystallized growth at low temperature. The observed p-type ZnO films will open the door for practical applications in various oxide electronic devices. (C) 2001 Elsevier Science B.V. All rights reserved.

  • Magnetic and electric properties of transition-metal-doped ZnO films

    K Ueda, H Tabata, T Kawai

    APPLIED PHYSICS LETTERS   79 ( 7 ) 988 - 990  2001年08月  [査読有り]

     概要を見る

    3d-transition-metal-doped ZnO films (n-type Zn1-xMxO (x=0.05-0.25): M=Co, Mn, Cr, Ni) are formed on sapphire substrates using a pulsed-laser deposition technique, and their magnetic and electric properties are examined. The Co-doped ZnO films showed the maximum solubility limit. Some of the Co-doped ZnO films exhibit ferromagnetic behaviors with the Curie temperature higher than room temperature. The magnetic properties of Co-doped ZnO films depend on the concentration of Co ions and carriers. (C) 2001 American Institute of Physics.

  • Control of magnetic properties in LaCrO3-LaFeO3 artificial superlattices

    K Ueda, H Tabata, T Kawai

    JOURNAL OF APPLIED PHYSICS   89 ( 5 ) 2847 - 2851  2001年03月  [査読有り]

     概要を見る

    The magnetic properties of LaFeO3-LaCrO3 superlattices have been artificially controlled by adjusting the atomic order of the B site ions via changes of the stacking direction of the [100], [110] and [111] planes and adjustment of the stacking periodicity. When Fe and Cr layers are atomically stacked along the [111] direction, ferromagnetism appears. In the case of superlattices growing along the &lt; 100 &gt; and [110] directions, antiferromagnetic properties appear, and the Neel temperature changes systematically as the stacking periodicity increases. Although the total number of Fe and Cr ions are the same in the (100), (110) and (111) stacking planes, different magnetic properties can be created in artificial superlattices. (C) 2001 American Institute of Physics.

  • Atomic ordering in the LaFe0.5Mn0.5O3 solid solution film

    K Ueda, Y Muraoka, H Tabata, T Kawai

    APPLIED PHYSICS LETTERS   78 ( 4 ) 512 - 514  2001年01月  [査読有り]

     概要を見る

    LaFe0.5Mn0.5O3 solid solution films have been formed on SrTiO3 (111) substrates using a pulsed laser deposition technique and their magnetic properties have been examined. The films showed ferromagnetic (or ferromagnetic) behavior with a Curie temperature of 380 K and the saturation magnetization was estimated to be about 1.5 mu (B) per magnetic ion site (B site). The x-ray photoemission spectra indicated that this behavior was due to the partial ordering of magnetic ions (Fe and Mn ions) which is caused by the charge disproportion between Fe and Mn ions under the film formation conditions. (C) 2001 American Institute of Physics.

  • Preparation and thickness dependence of magnetic properties of (111)-oriented Mg1.5FeTi0.5O4 spinel films on sapphire by pulsed laser deposition technique

    Y Muraoka, K Ueda, H Tabata, T Kawai

    VACUUM   59 ( 2-3 ) 622 - 627  2000年11月  [査読有り]

     概要を見る

    Thin films of (1 1 1)-oriented Mg1.5FeTi0.5O4 spinel have been successfully prepared by a pulsed laser deposition (PLD) technique on alpha -Al2O3 (0001) substrates. The value of the lattice parameter of the (1 1 1) out-of-plane and the Neel temperature of the films depend on the film thickness. The spin-glass behavior has been observed with a freezing temperature of 100 K, which is 80 K higher than that of the bulk material. This freezing temperature is reduced by increasing the oxygen pressure during film preparation. These results show that the PLD technique is promising not only for obtaining thin films of oxide materials under a wide range of conditions but also for controlling the magnetic properties of films. (C) 2000 Elsevier Science Ltd. All rights reserved.

  • Control of the magnetic and electric properties of low-dimensional SrRuO3-BaTiO3 superlattices

    K Ueda, H Saeki, H Tabata, T Kawai

    SOLID STATE COMMUNICATIONS   116 ( 4 ) 221 - 224  2000年  [査読有り]

     概要を見る

    Artificial superlattices of SrRuO3 and BaTiO3 were formed on SrTiO3 (110) substrates with various stacking periodicities and their magnetic and electric properties were examined. The Curie temperature and the magnetization of the superlattices decreased as the stacking periodicity decreased. Antiferromagnetic behaviors and the anisotropy of resistivity were observed in a two- by five-layer (2/5) superlattice. Low-dimensional effects appeared strongly in the 2/5 superlattice. (C) 2000 Elsevier Science Ltd. All rights reserved.

  • Artificial control of spin order and magnetic properties in LaCrO3-LaFeO3 superlattices

    K Ueda, H Tabata, T Kawai

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   38 ( 12A ) 6690 - 6693  1999年12月  [査読有り]

     概要を見る

    Magnetic properties have been artificially controlled in LaFeO3-LaCrO3 superlattices by arranging the atomic order of B site inns with changing the stacking direction and periodicity. When Fe and Cr layers are atomically stacked along the (111) direction, ferromagnetism appears, as shown in our previous study. In the case of the superlattices formed along the (100) direction, on the other hand. an antiferromagneiic property appears anal the Neel temperatures systematically change from 250 K to &gt; 400 K, corresponding to the stacking periodicity. Although the total numbers of Fe and Cr ions are the same in (111) and (100) stacking, quite a different magnetic character can be created in the artificial superlattices.

  • Atomic arrangement and magnetic properties of LaFeO3-LaMnO3 artificial superlattices

    K Ueda, H Tabata, T Kawai

    PHYSICAL REVIEW B   60 ( 18 ) R12561 - R12564  1999年11月  [査読有り]

     概要を見る

    Artificial superlattices of LaFeO3-LaMnO3 were formed on SrTiO3 (111), (100), and (110) substrates with various stacking periodicity using a pulsed laser deposition technique, and their magnetic properties were controlled by altering the ordering of magnetic ions (Fe or Mn). For superlattices constructed on the (111) plane, all the superlattices showed ferromagnetic (or ferrimagnetic) behaviors and the same Curie temperatures (T-C) at 230 K. The magnetization was reduced as the stacking periodicity of the superlattices decreased. On the other hand, in the case of superlattices formed on (110) or (100) substrates, the increase of the spin frustration effect at the LaFeO3-LaMnO3 interface with decreasing the stacking periodicity caused a reduction of T-C and magnetization. In particular, spin-glass-like behavior was observed in superlattices of less than 3/3 stacking periodicity. [S0163-1829(99)50442-6].

  • Coexistence of ferroelectricity and ferromagnetism in BiFeO3-BaTiO3 thin films at room temperature

    K Ueda, H Tabata, T Kawai

    APPLIED PHYSICS LETTERS   75 ( 4 ) 555 - 557  1999年07月  [査読有り]

     概要を見る

    (Bi0.7Ba0.3) (Fe0.7Ti0.3)O-3 films have been constructed on Nb-doped SrTiO3 (100) by the pulsed-laser deposition technique, and their physical properties have been examined. The films exhibit both ferroelectricity and ferromagnetism (weak ferromagnetism) with P-r=2.5 mu C/cm(2) and M-r=0.2 emu/g at room temperature. The film-thickness dependence of their magnetic and electric properties (size effect) is also discussed simultaneously. The dielectric constants of the films decrease with reducing film thickness below 1000 Angstrom. The magnetic Curie temperature of the films, on the other hand, does not change at all down to 250 Angstrom. (C) 1999 American Institute of Physics. [S0003-6951(99)02130-0].

  • Size effect of ferroelectric and ferromagnetic properties of bi-based perovskite type materials

    H Tabata, K Ueda, T Kawai

    FERROELECTRIC THIN FILMS VII   541   437 - 442  1999年  [査読有り]

     概要を見る

    Bismuth-based-layer-structure ferroelectric films have been formed epitaxially on Nb-doped SrTiO3 substrates by pulsed laser deposition (PLD). These films show an atomically smooth surface with a wide terrace of 100 nm similar to 200 nm, as observed by atomic force microscopy (AFM) which is ideal for measuring such properties. Thin films of (Bi-0.7, Ba-0.3) (Fe-0.7, Ti-0.3)O-3 exhibit both ferroelectric and ferromagnetic (weak ferromagnetism) properties at room temperature. In these samples, a size effect is discussed at the same time.

  • Artificial Control of Magnetic and Magnetoresistive Properties in the Perovskite Manganites Superlattices and Their Multilayers with Organics

    H. Tabata, K. Ueda, H. Matsui, H. Saeki, T. Kawai

    Mater. Res. Soc. Proc.   602   339-348  1999年  [査読有り]

  • Construction of ferroelectric and/or ferromagnetic superlattices by laser MBE and their physical properties

    H Tabata, K Ueda, T Kawai

    MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY   56 ( 2-3 ) 140 - 146  1998年11月  [査読有り]

     概要を見る

    We have constructed ferroelectric and/or ferromagnetic superlattices by a layer-by-layer successive deposition technique with a laser MBE. An ideal hetero-epitaxy can be obtained due to the similar crystal structure of the perovskite type ferroelectric BaTiO(3), SrTiO(3), Bi-based layered compounds and ferro- or antiferromagnetic LaFeO(3), LaCrO(3), (La,Sr)MnO(3). In both superlattices, strain effect plays an important role for deterring their physical properties. In the Bi-based layer structured superlattices, we have controlled dielectric constant and ferroelectric properties. We also control the spin order on LaFeO(3)/LaCrO(3) superlattices formed on SrTiO(3)(111) and (100) substrate. Such a spin structure(ferromagnetic order) cannot be realized in bulk samples. (C) 1998 Elsevier Science S.A. All rights reserved.

  • Ferromagnetism in LaFeO3-LaCrO3 superlattices

    K Ueda, H Tabata, T Kawai

    SCIENCE   280 ( 5366 ) 1064 - 1066  1998年05月  [査読有り]

     概要を見る

    Ferromagnetic spin order has been realized in the LaCrO3-LaFeO3 superlattices. Ferromagnetic coupling between Fe3+ and Cr3+ through oxygen has long been expected on the basis of Anderson, Goodenough, and Kanamori rules. Despite many studies of Fe-O-Cr-based compounds, random positioning of Fe3+ and Cr3+ ions has frustrated the observation of ferromagnetic properties. By creating artificial superlattices of Fe3+ and Cr3+ layer along the [111] direction, ferromagnetic ordering has been achieved.

  • Brain mimetic and the super five sense sensors formed by the combination of ferroelectric materials

    H. Tabata, H. Matsui, K. Ueda, T. Kawai

    The 4th Int. Conf. On Intelligent Materials Proc.     266-267  1998年  [査読有り]

  • Formation of ferromagnetic/ferroelectric superlattices by a laser MBE and their electric & magnetic properties

    H Tabata, K Ueda, T Kawai

    SCIENCE AND TECHNOLOGY OF MAGNETIC OXIDES   494   201 - 212  1998年  [査読有り]

     概要を見る

    We have constructed artificial superlattices with a combination of magnetic/magnetic and ferroelectric/ferromagnetic materials using a laser ablation technique. An ideal hetero-epitaxy can be obtained due to the similar crystal structure of the perovskite type di/ferroelectric BaTiO3, Pb(Zr,Ti)O-3 (so-called PZT), SrTiO3 and ferro/antiferromagnetic LaFeO3, LaCrO3, (La,Sr)MnO3. First of all, we have controlled ferromagnetic order on LaFeO3/LaCrO3 superlattices formed on SrTiO3(111) substrate. Such a spin structure(ferromagnetic order) can't be got in bulk condition. In the heterostructured ferromagnetic/ferroelectric devices, (La,Sr)MnO3/PZT there are remarkable and interesting phenomena. The electric properties of the ferromagnetic material can be controlled by the piezoelectric effect via distortion of the crystal structure.

  • Formation of ferroelectric/ferromagnetic functionally grated materials by Laser MBE and their physical properties

    H. Tabata, H. Tanaka, K. Ueda, T. Kawai

    Proc. of 9th Functionally Grated Materials Symp.     247-252  1997年  [査読有り]

  • Theoretical study and comparison with experiments for atacamite, Cu2Cl(OH)(3)

    K Ueda, S Takamizawa, W Mori, S Kubo, K Yamaguchi

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS   306   33 - 40  1997年

     概要を見る

    The dependency of the magnetic susceptibility on temperature has elucidated that the mineral atacamite Cu2Cl(OH)(3) has the antiferromagnetic property. In order to explain this behavior and the spin arrangement derived from experimental studies, the ab initio UHF MO and UNO CASCI calculations were carried out for the tetranuclear cluster of copper(II), Cu4Cl(OH)(3), which is the constitution in the atacamite crystal structure. The results of the CASCI calculations appreciate the relative stabilities among various spin arrangements for the tetranuclear cluster, being consistent with the experiments.

  • Calculation of magnetization by path integral method II

    T. Kawakami, H. Nagao, K. Ueda, W. Mori, K. Yamaguchi

    Mol. Cryst. Liq. Cryst.   286   177-184  1996年

  • Magnetic properties of basic copper(II) formates

    K Ueda, S Takamizawa, W Mori, K Yamaguchi

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS   285   339 - 344  1996年

     概要を見る

    Cu(HCOO)(OH) exhibits a strong ferromagnetic interaction (theta =+43K). The susceptibility shows a sharp maximum at T-m=21K and a plateau below 12K. This magnetic behavior is characteristic of antiferromagnetic materials. The spin-flop behavior is observed below T-m. To examine the spin-flop behavior of Cu(HCOO)(OH), magnetic phase diagram was drawn up. Magnetic phase diagram of Cu(DCOO)(OD) was also constructed to examine whether magnetic interaction between layers is due to hydrogen bond or not. Between them there is little difference in the phase diagram, but there is a remarkable difference in the hysteresis curves at 2K. Besides, temperature dependence of susceptibility and hysteresis curve at 1.8K of Cu-3(HCOO)(2)(OH)(4) was measured. In consequence it was found that this material also showed spin-flop behavior.

▼全件表示

書籍等出版物

  • 次世代パワー半導体の開発・評価と実用化

    監修:岩室 憲幸( 担当: 分担執筆,  担当範囲: ダイヤモンド半導体を用いた耐高温デバイスの作製と高性能化(第1編第3章第4節))

    エヌ・ティー・エス  2022年02月 ISBN: 9784860437671

  • New Topics in Josephson Junctions and Superconductivity Research (chapter 5) Low-Temperature Synthesis of Superconducting MgB2 Thin Films for Electronics Applications

    K. Ueda, M. Naito( 担当: 共著)

    Nova Science Publisher Inc.  2007年

  • Studies of high temperature superconductors-Growth of superconducting MgB2 thin films

    K. Ueda, M. Naito( 担当: 共著)

    Nova Science Publishers Inc  2003年

Misc

  • イオンビームアシストスパッタ法によるCo2MnSi薄膜の低温エピタキシャル成長

    植田研二, 浅野秀文

    電子情報通信学会技術研究報告(信学技報)   114 ( 234 ) MR2014-17  2014年10月

    速報,短報,研究ノート等(学術雑誌)  

  • MgAl2O4基板上に成長した格子整合系ホイスラー合金人工格子の結晶構造と磁気特性の相関

    宮脇哲也, 高橋一成, 深谷直人, 植田研二, 浅野秀文

    電子情報通信学会技術研究報告. MR, 磁気記録   110 ( 2011-03-04 ) 27-31  2011年

    速報,短報,研究ノート等(学術雑誌)  

  • CoFe2O4/Ba0.7Sr0.3TiO3複合構造のマルチフェロイック特性

    田代裕樹, 小林耕平, 小林智, 宮脇哲也, 植田研二, 浅野秀文

    電子情報通信学会技術研究報告. MR, 磁気記録   110 ( 2011-03-04 ) 33-38  2011年

    速報,短報,研究ノート等(学術雑誌)  

  • MgAl2O4基板上のホイスラー合金薄膜・人工格子の構造と磁性

    竹田陽一, 深谷直人, 高橋一成, 藤田裕人, 植田研二, 浅野秀文

    映像情報メディア学会技術報告(ITE technical report)   34 ( 13 ) 45 - 51  2010年03月  [査読有り]

受賞

  • APEX/JJAP編集貢献賞

    2015年04月   日本応用物理学会  

共同研究・競争的資金等の研究課題

  • グラフェン/ダイヤモンド接合の巨大光伝導度変調機構の解明とデバイス応用

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    2021年04月
    -
    2024年03月
     

    植田 研二

  • ダイヤモンド/グラフェン接合を用いた脳型記憶撮像デバイスの作製

    池谷科学技術振興財団  池谷科学技術振興財団研究助成

    研究期間:

    2021年04月
    -
    2022年03月
     

  • グラフェン/ダイヤモンド接合を用いた新規光イメージングメモリの作製

    住友電工グループ社会貢献基金  住友電工グループ社会貢献基金研究助成

    研究期間:

    2020年10月
    -
    2022年03月
     

  • グラフェン/ダイヤモンド接合を用いた新規高効率パワーデバイスの開発

    岩谷直治記念財団  岩谷科学技術研究助成金

    研究期間:

    2020年04月
    -
    2021年03月
     

  • カーボン光メモリスタを用いた新規光デバイスの開発

    日本板硝子財団工学助成会  日本板硝子財団工学助成会研究助成

    研究期間:

    2019年04月
    -
    2020年04月
     

  • ダイヤモンド/グラフェン接合を用いた光検出と記憶を同時に行う新規受光素子の作製

    光科学技術研究振興財団  光科学技術研究振興財団研究助成金

    研究期間:

    2018年01月
    -
    2019年12月
     

    植田研二

  • ダイヤモンド半導体への高効率スピン注入と低損失スピン輸送

    日本学術振興会  科学研究費助成事業

    研究期間:

    2016年04月
    -
    2019年03月
     

  • ダイヤモンド/グラフェン接合を用いた新規受光・記憶素子の開発

    立松財団  立松財団研究助成

    研究期間:

    2017年09月
    -
    2018年08月
     

    植田 研二

  • ダイヤモンド/グラフェン接合を用いた記憶機能を有する新規イメージセンサの創製

    村田学術振興財団  村田学術振興財団研究助成

    研究期間:

    2017年08月
    -
    2018年07月
     

    植田 研二

  • グラフェン/ダイヤモンド接合を用いた高性能光検出デバイスの作製と動作機構の解明

    豊秋奨学会  豊秋奨学会研究助成金

    研究期間:

    2016年10月
    -
    2017年09月
     

    植田 研二

  • 完全スピン偏極ゼロギャップ半導体の創製とスピンデバイス応用

    日本学術振興会  科学研究費助成事業

    研究期間:

    2015年04月
    -
    2017年03月
     

  • 強磁性ハーフメタル/ダイヤモンド半導体ヘテロ接合を用いた新規スピンデバイスの開発

    日本学術振興会  科学研究費助成事業

    研究期間:

    2012年04月
    -
    2015年03月
     

  • スピン三重項高温超伝導電子対の研究

    日本学術振興会  科学研究費助成事業

    研究期間:

    2011年04月
    -
    2013年03月
     

    浅野秀文, 植田研二

  • ダイヤモンド半導体/強磁性体ハイブリッド構造による新規スピンデバイスの創製

    日本学術振興会  科学研究費助成事業

    研究期間:

    2010年04月
    -
    2012年03月
     

    植田 研二

  • 高機能スピン制御材料の創製

    日本学術振興会  科学研究費助成事業

    研究期間:

    2008年04月
    -
    2011年03月
     

    浅野 秀文

▼全件表示

講演・口頭発表等

  • Brain-mimic optoelectronic memory functions of vertically aligned graphene/diamond heterojunctions

    Y. Ito, Y. Mizuno, K. Ueda

    2021 MRS fall meeting, On-site, virtual hybrid conference  

    発表年月: 2021年12月

  • Optically-controllable synaptic characters of vertically aligned graphene/diamond junctions

    K. Ueda, Y. Mizuno, Y. Ito

    Memrisys 2021  

    発表年月: 2021年11月

  • 垂直配向グラフェン/ダイヤモンド接合の光記憶特性制御

    伊藤 悠河, 水野 雄貴, 植田 研二

    2021年度第82回応用物理学会秋季学術講演会  

    発表年月: 2021年09月

  • 逆ペロブスカイト窒化物ノンコリニア反強磁性体 Mn3AN(A= Ga, Sn)薄膜における異常ホール効果

    加藤 大雅, 園田 航, 松浦 健人, 強 博文, 羽尻 哲也, 植田 研二, 浅野 秀文

    2021年度第82回応用物理学会秋季学術講演会  

    発表年月: 2021年09月

  • ノンコリニア反強磁性体逆ペロブスカイト窒化物薄膜における異常ホール効果

    園田 航, 加藤大雅, 松浦健人, 強 博文, 羽尻哲也, 植田研二, 浅野秀文

    第45回日本磁気学会学術講演会  

    発表年月: 2021年08月

  • Various optoelectronic memory functions of vertically aligned graphene/diamond heterojunctions

    K. Ueda, Y. Mizuno, Y. Ito

    International conference on new diamond and nano carbons 2020/2021 (NDNC2020/21), Virtual conference (Kanazawa, Japan)  

    発表年月: 2021年06月

  • ダイヤモンド/グラフェン(炭素sp3-sp2)接合の作製とデバイス応用

    植田研二  [招待有り]

    第67回応用物理学会春季学術講演会   (上智大学)  日本応用物理学会  

    発表年月: 2020年03月

  • Structural insight using anomalous XRD into Mn2CoAl inverse Heusler alloy _lms fabricated by magnetron sputtering, IBAS and MBE techniques

    L. Kumara, H. Tajiri, J. Wang, Z. Chen, W. Zhou, Y. Sakuraba, K. Ueda, S. Yamada, K. Hamaya, K. Hono

    第43回日本磁気学会学術講演会   (京都大学) 

    発表年月: 2019年09月

  • トポロジカルデバイス応用に向けたLaBi 薄膜の作製と磁気伝導特性

    鈴木健太, 植田研二, 羽立康浩, 浅野秀文

    第43回日本磁気学会学術講演会   (京都大学) 

    発表年月: 2019年09月

  • プラズマアニール法によるダイヤモンド上グラフェンの作製

    今井 祐太, 植田 研二, 浅野 秀文

    第80回日本応用物理学会秋季学術講演会   (北海道大学) 

    発表年月: 2019年09月

  • Graphene/diamond (carbon sp2-sp3) heterojunctions as novel photoelectronic devices

    Y. Imai, K. Ueda, Y. Mizuno, H. Asano

    SSDM2019   (Nagoya) 

    発表年月: 2019年09月

  • グラフェン/ダイヤモンド接合の作製と電子デバイス応用

    水野雄貴, 今井祐太, 植田研二

    第4回表面界面の機能創成とデバイス応用セミナー   (名古屋大学) 

    発表年月: 2019年08月

  • Carbon nanowalls/diamond heterojunctions as novel photo-switching memory devices

    Y. Imai, K. Ueda, H. Itou, Y. Mizuno, H. Asano

    CSW (Compound Semiconductor Week) 2019   (Nara, Japan) 

    発表年月: 2019年05月

  • Graphene/diamond heterojunctions as novel photo-switching memory devices

    K. Ueda  [招待有り]

    CCMST (Collaborative Conference on Materials Science and Technology) 2018   (Beijing, China)  CCMST (Collaborative Conference on Materials Science and Technology) 2018  

    発表年月: 2018年09月

  • カーボンナノウォール/ダイヤモンド光メモリスタの動作機構

    伊藤 秀治, 植田 研二, 浅野 秀文

    第79回日本応用物理学会秋季学術講演会  

    発表年月: 2018年09月

  • トポロジカル半金属LaBi薄膜の作製と特性評価

    森 雅斗, 植田 研二, 鈴木 健太, 浅野 秀文

    第79回日本応用物理学会秋季学術講演会  

    発表年月: 2018年09月

  • グラフェン/ダイヤモンド(炭素sp2/sp3)接合を用いた光メモリスタの作製とデバイス応用

    植田 研二  [招待有り]

    第3回「表面界面の機能創成とデバイス応用」セミナー   表面界面の機能創成とデバイス応用合同セミナー委員会  

    発表年月: 2018年08月

  • カーボンナノウォール/ダイヤモンド接合における光誘起巨大伝導度変調

    伊藤 秀治, 植田 研二, 浅野 秀文

    第65回応用物理学会春季学術講演会   (早稲田大学) 

    発表年月: 2018年03月

  • Ambipolar transport in Mn2CoAl spin gapless semiconductors by ionic liquid gating

    K. Ueda, S. Hirose, M. Mori, H. Asano

    MRS2017 fall meetings   (Boston, USA) 

    発表年月: 2017年11月

  • Fabrication of carbon nanowalls/ diamond heterojunctions and their electronic properties

    K. Ueda, H. Itou, H. Asano

    MRS2017 fall meetings   (Boston, USA) 

    発表年月: 2017年11月

  • Multiferroic properties of heterostructures using antiferromagnetic insulator SmFeO3

    M. Kuroda, T Hajiri, N. Tanahashi, K. Ueda, H. Asano

    62nd Annual Conference on Magnetism and Magnetic Materials  

    発表年月: 2017年11月

  • ホイスラースピンギャップレス半導体Mn2CoAl薄膜の作製とデバイス応用

    植田 研二  [招待有り]

    第五回ホイスラー化合物熱電素子材料による廃熱発電研究会  

    発表年月: 2017年09月

  • Ambipolar transport and modulation of electronic properties of Mn2CoAl films by ionic liquid gating

    K. Ueda, S. Hirose, M. Mori, H. Asano

    SSDM2017   (Sendai, Japan) 

    発表年月: 2017年09月

  • ホイスラースピンギャップレス半導体Mn2CoAlにおける電界誘起両極性伝導

    植田 研二, 広瀬 慎吾, 森 雅斗, 浅野 秀文

    日本金属学会2017年秋季講演大会   (北海道大学) 

    発表年月: 2017年09月

  • カーボンナノウォール/ダイヤモンドヘテロ接合の作製と電気特性

    伊藤 秀治, 植田 研二, 浅野 秀文

    第78回日本応用物理学会秋季学術講演会   (福岡国際会議場) 

    発表年月: 2017年09月

  • ノンコリニア型反強磁性絶縁体SmFeO3のエピタキシャル薄膜における磁化のエンハンスメント

    棚橋 直也, 黒田 基規, 羽尻 哲也, 植田 研二, 浅野 秀文

    第78回日本応用物理学会秋季学術講演会   (福岡国際会議場) 

    発表年月: 2017年09月

  • Photoconductive characteristics of graphene/diamond heterojunctions

    K. Ueda  [招待有り]

    CCMR(Collaborative Conference on Materials Research)2017   (Jezu, Korea) 

    発表年月: 2017年06月

  • 反強磁性絶縁体SmFeO3を用いたマルチフェロイック積層膜の作成と評価

    黒田 基規, 棚橋 直也, 羽尻 哲也, 植田 研二, 浅野 秀文

    第64回 応用物理学会春季学術講演会  

    発表年月: 2017年03月

  • Unusual magnetoresistance in heusler compounds antiferromagnet/ferromagnet bilayers

    M. Matsushita, T. Hajiri, K. Ueda, H. Asano

    MMM 2016   (New Orleans, USA) 

    発表年月: 2016年10月

  • Strain effect and multiferroic properties of Sr2CrReO6/BaxSr1-xTiO3 Heterostructures

    J. So, M. Kuroda, T. Hajiri, K. Ueda, H. Asano

    WOE23 (International workshop on oxide electronics)   (Nanjing, China) 

    発表年月: 2016年10月

  • Strain tuning and superconducting properties of infinite-layer Sr1-xLaxCuO2 thin films on BaySr1-yTiO3 buffer layers

    K. Morioka, K. Sakuma, M. Ito, T. Hajiri, K. Ueda, H. Asano

    WOE23 (International workshop on oxide electronics)   (Nanjing, China) 

    発表年月: 2016年10月

  • Fabrication of graphene/diamond heterojunctions and their electronic properties

    K. Ueda, S.Tanaka, H. Asano

    SSDM 2016   (Tsukuba, Japan) 

    発表年月: 2016年09月

  • 窒素組成制御したMn3GaN薄膜の作製と評価

    ソジョンミン, 羽尻哲也, 植田研二, 浅野秀文

    第77回 応用物理学会秋季学術講演会   (朱鷺メッセ(新潟)) 

    発表年月: 2016年09月

  • 逆ペロブスカイト窒化物Co3FeN/Mn3GaNヘテロ接合の作製と交換結合特性

    黒木庸次, 安藤弘紀, 羽尻哲也, 植田研二, 浅野秀文

    第77回 応用物理学会秋季学術講演会   (朱鷺メッセ(新潟)) 

    発表年月: 2016年09月

  • 歪による無限層Sr1-xLaxCuO2スパッタ薄膜の超伝導特性制御

    作間啓太, 伊藤雅崇, 植田研二, 三浦 正志, 浅野秀文

    第77回 応用物理学会秋季学術講演会   (朱鷺メッセ(新潟)) 

    発表年月: 2016年09月

  • グラフェン/ダイヤモンド接合における光・熱誘起伝導度変化

    植田研二, 浅野秀文

    第77回 応用物理学会秋季学術講演会   (朱鷺メッセ(新潟)) 

    発表年月: 2016年09月

  • Photo and/or heat induced large conductivity change in graphene/diamond heterojunctions

    K. Ueda, S.Aichi, H. Asano

    ICDCM (International conference on diamond and carbon materials) 2016   (Montpelier, France) 

    発表年月: 2016年09月

  • 電子ドープ型無限層超伝導Sr1-xLaxCuO2薄膜における引張歪効果

    伊藤 雅崇, 作間 啓太, 羽尻 哲也, 植田 研二, 浅野 秀文

    第158回日本金属学会春季講演大会   (九州大学) 

    発表年月: 2016年03月

  • 歪制御した無限層Sr0.125La0.875CuO2スパッタ薄膜の超伝導特性

    作間 啓太, 伊藤 雅崇, 羽尻 哲也, 植田 研二, 浅野 秀文

    第63回応用物理学会春季学術講演会   (東京工業大学) 

    発表年月: 2016年03月

  • Spin injection from half-metallic Heusler Co2MnSi into diamond semiconductors

    K. Ueda, M. Nishiwaki, H. Asano

    MMM | Intermag 2016 Joint conference   (San Diego, USA) 

    発表年月: 2016年01月

  • Magnetic and electronic properties of epitaxial Mn2CoAl films

    K. Ueda, S. Hirose, S. Aichi, T. Hajiri, H. Asano

    SSDM 2015   (Hokkaido, Japan) 

    発表年月: 2015年09月

  • 異方性磁気抵抗効果を用いたホイスラー合金積層膜Fe2CrSi/Ru2MnGeの研究

    松下将輝, 羽尻哲也, 植田研二, 浅野秀文

    日本金属学会2015年秋期講演大会   (九州大学) 

    発表年月: 2015年09月

  • Mn2CoAlエピタキシャル薄膜の作製と電気・磁気特性

    広瀬慎吾, 植田研二, 愛知慎也, 羽尻哲也, 浅野秀文

    日本金属学会2015年秋期講演大会   (九州大学) 

    発表年月: 2015年09月

  • 銅触媒を用いたアニール法によるダイヤモンド表面のグラフェン形成

    愛知慎也, 植田研二, 広瀬慎吾, 浅野秀文

    第76回 応用物理学会秋季学術講演会   (名古屋国際会議場) 

    発表年月: 2015年09月

  • Mn2CoAl スピンギャップレス半導体薄膜の作製と特性評価

    広瀬慎吾, 植田研二, 愛知慎也, 羽尻哲也, 浅野秀文

    第76回 応用物理学会秋季学術講演会   (名古屋国際会議場) 

    発表年月: 2015年09月

  • 逆ペロブスカイト窒化物交換結合膜における電流誘起磁化スイッチングの成長方位による影響

    黒木 庸次, 安藤 弘紀, 河合 俊介, 羽尻 哲也, 植田 研二, 浅野 秀文

    第76回 応用物理学会秋季学術講演会   (名古屋国際会議場) 

    発表年月: 2015年09月

  • Sr2CrReO6/BaxSr1-xTiO3 ヘテロ積層構造における歪み効果と電気磁気特性

    伊東 和徳, 作間 啓太, ソ ジョンミン, 羽尻 哲也, 植田 研二, 浅野 秀文

    第76回 応用物理学会秋季学術講演会   (名古屋国際会議場) 

    発表年月: 2015年09月

  • スピンギャップレス半導体のデバイス応用に向けたMn2CoAl 薄膜の作製

    広瀬慎吾, 植田研二, 愛知慎也, 羽尻哲也, 浅野秀文

    第39回 日本磁気学会学術講演会   (名古屋大学) 

    発表年月: 2015年09月

  • 異方性磁気抵抗効果を用いたホイスラー合金 ハーフメタル強磁性/反強磁性Fe2CrSi /Ru2MnGe積層膜の研究

    羽尻哲也, 松下将輝, 植田研二, 浅野秀文

    第39回 日本磁気学会学術講演会   (名古屋大学) 

    発表年月: 2015年09月

  • 逆ペロブスカイト窒化物交換結合膜における電流駆動磁化スイッチングの成長方位依存性

    安藤弘紀, 黒木庸次, 羽尻哲也, 植田研二, 浅野秀文

    第39回 日本磁気学会学術講演会   (名古屋大学) 

    発表年月: 2015年09月

  • Fabrication of epitaxial Mn2CoAl films for spintronic applications using spin-gapless semiconductors

    K. Ueda, S. Hirose, M. Nishiwaki, T. Hajiri, H. Asano

    ICM (International conference on magnetism) 2015   (Barcelona, Spain) 

    発表年月: 2015年07月

  • Anisotropic magnetoresistance of Heusler-type half-metal ferromagnet and antiferromagnet bilayer thin films

    T. Hajiri, M. Matsushita, M. Nishiwaki, H. Tanaka, K. Ueda, H. Asano

    ICM (International conference on magnetism) 2015   (Barcelona, Spain) 

    発表年月: 2015年07月

  • Magnetic and Josephson properties of NbN junctions with a magnetic interlayer

    R. Takagi, S. Oh, T. Hajiri, K. Ueda, H. Asano

    ISEC (15th international superconductive electronics conference)   (Nagoya) 

    発表年月: 2015年06月

  • Direct formation of graphene on diamond by high-temperature annealing method using Cu catalyst

    S.Aichi, K. Ueda, H. Asano

    NDNC (New diamond and nano carbons) 2015   (Shizuoka) 

    発表年月: 2015年05月

  • Strain effect of a-axis oriented Sr1-xLaxCuO2 thin films grown on LaAlO3 substrates

    Y. He, M. Ito, T. Hajiri, K. Ueda, H. Asano

    INTERMAG 2015   (Beijing, China) 

    発表年月: 2015年05月

  • Magnetic and transport properties of antiperovskite nitride Co3FeN films

    S. Kawai, H. Ando, H. Sakakibara, Y. Kuroki, T. Hajiri, K. Ueda, H. Asano

    INTERMAG 2015   (Beijing, China) 

    発表年月: 2015年05月

  • Current induced magnetization switching in an antiperovskite nitride exchange-coupled bilayer

    Y. Kuroki, H. Sakakibara, H. Ando, S. Kawai, T. Hajiri, K. Ueda, H. Asano

    INTERMAG 2015   (Beijing, China) 

    発表年月: 2015年05月

  • Cu diamond Schottky diodes for high-temperature and high-power applications

    K. Ohtsuka, K. Ueda, S. Aichi, H. Asano

    ISPlasma2015  

    発表年月: 2015年03月

  • 無限層超伝導Sr1-xLaxCuO2 a軸成長膜における歪効果

    伊藤雅崇, 何 軼倫, 羽尻哲也, 植田研二, 浅野秀文

    第62回応用物理学会春季学術講演会  

    発表年月: 2015年03月

  • 逆ペロブスカイトCo3FeN薄膜の異方性磁気抵抗効果とスピン分極率

    榊原英樹, 黒木庸次, 安藤弘紀, 河合俊介, 羽尻哲也, 植田研二, 浅野秀文

    第62回応用物理学会春季学術講演会  

    発表年月: 2015年03月

  • 逆ぺロブスカイト窒化物交換結合膜における電流誘起磁化スイッチング

    安藤弘紀, 河合俊介, 榊原英樹, 黒木庸次, 羽尻哲也, 植田研二, 浅野秀文

    第62回応用物理学会春季学術講演会  

    発表年月: 2015年03月

  • ハーフメタル/BaxSr1-xTiO3ヘテロ積層構造における歪み効果と電気的特性

    蘇ジョンミン, 許方舟, 伊東和徳, 羽尻哲也, 植田研二, 浅野秀文

    第62回応用物理学会春季学術講演会  

    発表年月: 2015年03月

  • ペロブスカイトハーフメタル/強誘電体ヘテロ構造のマルチフェロイック特性

    浅野秀文, 蘇ジョンミン, 許方舟, 伊東和徳, 羽尻哲也, 植田研二

    第62回応用物理学会春季学術講演会  

    発表年月: 2015年03月

  • Co2MnSi/diamond Schottky junctions for spintronic applications

    K. Ueda, H. Asano

    EMN-fall meetings 2014  

    発表年月: 2014年11月

  • Epitaxial growth and properties of antiperovskite nitride Mn3GaN/Co3FeN bilayers

    H. Sakakibara, H. Ando, Y. Kuroki, S. Kawai, K. Ueda, H. Asano

    59th Annual Magnetism & Magnetic Materials conference  

    発表年月: 2014年11月

  • Low temperature growth of Co2MnSi films on diamond semiconductor by ion beam assisted sputtering

    M. Nishiwaki, K. Ueda, S. Aichi, H. Asano

    59th Annual Magnetism & Magnetic Materials conference  

    発表年月: 2014年11月

  • The magneto-optical Kerr effect (MOKE) study of Sr2CrReO6 thin films

    J. So, K. Ueda, H. Asano

    59th Annual Magnetism & Magnetic Materials conference  

    発表年月: 2014年11月

  • Magnetic properties and spin polarization of double perovskite SrLaVRuO6 thin films

    K. Itou, K. Ueda, T. Shinno, H. Asano

    59th Annual Magnetism & Magnetic Materials conference  

    発表年月: 2014年11月

  • High-temperature and high-voltage characteristics of diamond Schottky diodes

    K. Ueda

    2nd French-Japanese Workshop on Diamond Power Devices  

    発表年月: 2014年10月

  • イオンビームアシストスパッタ法によるCo2MnSi薄膜の低温エピタキシャル成長

    植田研二, 浅野秀文

    電子情報通信学会、磁気記録・情報ストレージ研究会(MR)  

    発表年月: 2014年10月

  • c軸成長無限層超伝導体Sr1-xLaxCuO2におけるバッファ層BaxSr1-xTiO3による歪効果

    伊藤雅崇, 何 軼倫, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文

    日本金属学会、2014年秋季講演大会  

    発表年月: 2014年09月

  • 二重ペロブスカイトSrLaVRuO6薄膜の磁性とスピン分極率

    伊東和徳, 新野貴士, 植田研二, 浅野秀文

    日本金属学会、2014年秋季講演大会  

    発表年月: 2014年09月

  • 反応性スパッタ法で作製したCo3FeN薄膜の異方性磁気抵抗効果

    河合俊介, 榊原英樹, 安藤弘紀, 植田研二, 浅野秀文

    日本金属学会、2014年秋季講演大会  

    発表年月: 2014年09月

  • 反応性スパッタ法によるMgAl2O4バリアを用いたトンネル接合の作製と界面構造

    田中秀和, 稲垣圭真, 深谷直人, 植田研二, 浅野秀文

    日本金属学会、2014年秋季講演大会  

    発表年月: 2014年09月

  • Cu/ダイヤモンドショットキーダイオードの高温耐電圧特性

    植田研二, 河本圭太, 西脇雅人, 浅野秀文

    第75回応用物理学会秋季学術講演会  

    発表年月: 2014年09月

  • High-Temperature and High-Voltage Characteristics of Cu/Diamond Schottky Diodes

    K. Ueda, K. Kawamoto, S. Aichi, M. Nishiwaki, H. Asano

    SSDM 2014  

    発表年月: 2014年09月

  • High-temperature and high-voltage operation of Cu/diamond Schottky diodes

    K. Ueda, K. Kawamoto, H. Asano

    ICDCM (International conference on diamond and carbon materials) 2014  

    発表年月: 2014年09月

  • 逆ペロブスカイトCo3FeN薄膜の異方性磁気抵抗効果

    安藤弘紀, 榊原英樹, 河合俊介, 植田研二, 浅野秀文

    第38回 日本磁気学会学術講演会  

    発表年月: 2014年09月

  • Half-metallic Heusler/diamond heterojunctions for spintronic applications

    K. Ueda, H. Asano

    IUMRS-ICA 2014  

    発表年月: 2014年08月

  • Preparation and properties of Sr1-xLaxCuO2 thin films grown on BaxSr1-xTiO3 layers

    Y. He, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano

    ASC (Applied superconductivity conference )2014  

    発表年月: 2014年08月

  • The response to the magnetic field of critical current of NbN Josephson junctions with a ferromagnetic ultra thin layer

    R. Takagi, M. Itou, T. Miyawaki, K. Ueda, H. Asano

    ASC (Applied superconductivity conference )2014  

    発表年月: 2014年08月

  • Low temperature growth of epitaxial Co2MnSi films on lattice-matched MgAl2O4 substrates by ion-beam assisted sputtering

    M. Nishiwaki, K. Ueda, S. Aichi, T. Miyawaki, H. Asano

    Intermag 2014  

    発表年月: 2014年05月

  • Preparation and properties of ferromagnetic antiperovskite Co3FeN thin films

    H. Sakakibara, H. Ando, T. Miyawaki, K. Ueda, H. Asano

    Intermag 2014  

    発表年月: 2014年05月

  • イオンビームアシストスパッタリング法を用いた格子整合MgAl2O4基板上へのCo2MnSi薄膜の成長

    西脇雅人, 植田研二, 河本圭太, 愛知慎也, 浅野秀文

    第61回応用物理学会春季学術講演会   (青山学院大学) 

    発表年月: 2014年03月

  • Ba1-xSrxTiO3上の無限層Sr1-xLaxCuO2薄膜の歪み効果

    何軼倫, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文

    第61回応用物理学会春季学術講演会   (青山学院大学) 

    発表年月: 2014年03月

  • 反応性スパッタ法による逆ペロブスカイト型窒化物Co3FeN薄膜の作製

    安藤弘紀, 榊原英樹, 宮脇哲也, 植田研二, 浅野秀文

    第61回応用物理学会春季学術講演会   (青山学院大学) 

    発表年月: 2014年03月

  • 規則型二重ペロブスカイトSrLaVRuO6の磁性とスピン分極率

    伊東和徳, 新野貴士, 宮脇哲也, 植田研二, 浅野秀文

    IEEE Magnetics Society 名古屋支部若手研究会   (名古屋大学) 

    発表年月: 2014年02月

  • Strain Effects and Applications of Antiferromagnetic Heusler-alloy Thin Films

    H. Asano, N. Fukatani, T. Miyawaki, K. Ueda

    The Seven International Conference on Materials Engineering for Resources 2013 (ICMR)   (Akita, Japan) 

    発表年月: 2013年11月

  • Magnetic Schottky junctions using heterostructures of half-metallic Co2MnSi/diamond semiconductors

    K. Ueda, T. Soumiya, M. Nishiwaki, K. Kawamoto, T. Miyawaki, H. Asano

    58th Annual Magnetism and Magnetic Materials (MMM2013)   (Denver, USA) 

    発表年月: 2013年11月

  • Preparation and Characterization of Ordered Double Perovskite SrLaVMoO6 Thin Films

    T. Shinno, K. Sanbou, K. Sakuma, T . Miyawaki, K. Ueda, H. Asano

    International Conference on Solid State Devices and Materials(SSDM2013)   (Fukuoka, Japan) 

    発表年月: 2013年09月

  • Structural and transport properties in epitaxial Fe2CrSi/MgAl2Ox/Fe2CrSi structures

    K. Inagaki, N. Fukatani, H. Tanaka, T. Miyawaki, K. Ueda, H. Asano

    International Conference on Solid State Devices and Materials(SSDM2013)   (Fukuoka, Japan) 

    発表年月: 2013年09月

  • High-temperature characteristics of diamond Schottky diodes using various Schottky metals

    K. Kawamoto, K. Ueda, M. Nishiwaki, H. Asano

    International Conference on Solid State Devices and Materials(SSDM2013)   (Fukuoka, Japan) 

    発表年月: 2013年09月

  • Fabrication of half-metallic Co2MnSi/diamond Schottky junctions

    K. Ueda, M. Nishiwaki, T. Soumiya, K. Kawamoto, H. Asano

    International Conference on Solid State Devices and Materials(SSDM2013)   (Fukuoka, Japan) 

    発表年月: 2013年09月

  • 無限層構造Sr1-xLaxCuO2薄膜の a軸成長化とその特性

    何軼倫, 赤塚寛之, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文

    第74回応用物理学会秋季学術講演会   (同志社大学) 

    発表年月: 2013年09月

  • 強磁性CoFeを挿入した NbNジョセフソン接合の電気的特性

    髙木涼真, 宮脇哲也, 植田研二, 浅野秀文

    第74回応用物理学会秋季学術講演会   (同志社大学) 

    発表年月: 2013年09月

  • 逆ペロブスカイト窒化物Mn3GaN薄膜の電気的・磁気的特性

    榊原英樹, 小林洸, 宮脇哲也, 植田研二, 浅野秀文

    第74回応用物理学会秋季学術講演会   (同志社大学) 

    発表年月: 2013年09月

  • 二重ペロブスカイトSrLaVRuO6薄膜の磁気・伝導物性

    伊東和徳, 新野貴士, 宮脇哲也, 植田研二, 浅野秀文

    第74回応用物理学会秋季学術講演会   (同志社大学) 

    発表年月: 2013年09月

  • SrLaVMoO6 as a Strong Candidate for a Half-metallic Antiferromagnet

    K. Ueda, H. Asano

    2013 JSAP-MRS joint symposium   (京都) 

    発表年月: 2013年09月

  • Ferromagnetic Schottky junctions using half-metallic Co2MnSi/diamond heterostructures

    K. Ueda, M. Nishiwaki, T. Soumiya, K. Kawamoto, H. Asano

    2013 JSAP-MRS Joint symposium   (京都) 

    発表年月: 2013年09月

  • イオンビームアシストスパッタ法を用いたダイヤモンド半導体上へのハーフメタルCo2MnSi薄膜の低温成長

    西脇雅人, 植田研二, 宗宮嵩, 河本圭太, 宮脇哲也, 浅野秀文

    第37回日本磁気学会学術講演会   (北海道大学) 

    発表年月: 2013年09月

  • High temperature characteristics of diamond devices

    K. Ueda, H. Asano

    1st French-Japanese Workshop on Diamond power devices   (Chamonix, France) 

    発表年月: 2013年06月

  • High temperature stability of diamond Schottky junctions

    K. Ueda, K. Kawamoto, T. Soumiya, H. Asano

    NDNC (New Diamond and Nano Carbon conference) 2013   (Singapole) 

    発表年月: 2013年05月

  • Epitaxial growth of half-metallic Heusler alloy Co2MnSi on diamond semiconductors and their interfacial characteristics

    K. Ueda, T. Soumiya, M. Nishiwaki, K. Kawamoto, H. Asano

    NDNC (New Diamond and Nano Carbon conference) 2013   (Singapole) 

    発表年月: 2013年05月

  • 規則型二重ペロブスカイトSrLaVMoO6のスピン分極率

    新野貴士, 三宝勝利, 松島宏行, 宮脇哲也, 植田研二, 浅野秀文

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • ホイスラー強磁性/反強磁性積層膜における構造と界面磁性

    深谷直人, 榊原英樹, 稲垣圭真, 宮脇哲也, 植田研二, 浅野秀文

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • 超伝導NbN薄膜上に作製した交換結合膜の磁気特性

    吉原健彦, 髙木涼真, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • ダイヤモンドショットキー接合の高温安定性評価

    河本圭太, 植田研二, 宗宮嵩, 西脇雅人, 宮脇哲也, 浅野秀文

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • 低温成長ハーフホイスラーLaPtBi薄膜の電気伝導特性

    新美陽平, 杉本望実, 宮脇哲也, 深谷直人, 吉原健彦, 伊藤孝寛, 浅野秀文, 田中信夫

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • ダイヤモンド半導体/ハーフメタルCo2MnSiショットキー接合の作製

    宗宮嵩, 植田研二, 西脇雅人, 河本圭太, 宮脇哲也, 浅野秀文

    第60回応用物理学会春季学術講演会   (神奈川工科大学) 

    発表年月: 2013年03月

  • High temperature characteristics of Schottky diodes using diamond

    K. Ueda, K. Kawamoto, T. Soumiya, M. Nishiwaki, H. Asano

    ISPlasma2013   (名古屋) 

    発表年月: 2013年01月

  • Fabrication of diamond/Heusler heterojunctions for spintronic applications

    T. Soumiya, K. Ueda, K. Kawamoto, N. Fukatani, H. Asano

    ISPlasma2013   (名古屋) 

    発表年月: 2013年01月

  • Structural and magnetic properties in Heusler-type ferromagnet/antiferromagnet bilayers

    N. Fukatani, K. Inagaki, T. Miyawaki, K. Ueda, H. Asano

    12th Joint MMM/Intermag Conference   (シカゴ) 

    発表年月: 2013年01月

  • Growth and properties of a-axis oriented thin films of infinite-layer Sr1-xLaxCuO2

    H. Akatsuka, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano

    Applied Superconductivity Conference (ASC2012)   (Portland) 

    発表年月: 2012年10月

  • Preparation and properties of Ba0.7Sr0.3TiO3 / Mn3GaN heterostructures

    R. Suzuki, H. Tashiro, T. Miyawaki, K. Ueda, H. Asano

    International Conference of the Asian Union of Magnetics Societies (ICAUMS2012)   (奈良) 

    発表年月: 2012年10月

  • Growth and properties of epitaxial Fe2CrSi / AFM Ru2MnGe Heusler multilayers

    K. Inagaki, N. Fukatani, T. Miyawaki, K. Ueda, H. Asano

    International Conference of the Asian Union of Magnetics Societies (ICAUMS2012)   (奈良) 

    発表年月: 2012年10月

  • Epitaxial thin films of ordered double perovskite SrLaVMoO6

    T. Shinno, K. Sanbou, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano

    International Conference of the Asian Union of Magnetics Societies (ICAUMS2012)   (奈良) 

    発表年月: 2012年10月

  • Epitaxial growth of half-metallic ferromagnets Co2MnSi on diamond semiconductors

    T. Soumiya, K. Ueda, K. Kawamoto, N. Fukatani, H. Asano

    International Conference of the Asian Union of Magnetics Societies (ICAUMS2012)   (奈良) 

    発表年月: 2012年10月

  • Structure and valence band spectra of half-Heusler La-Pt-Bi thin films

    Y. Niimi, N. Sugimoto, T. Miyawaki, T. Yoshihara, N. Fukatani, K. Ueda, N. Tanaka, H. Asano

    International Conference of the Asian Union of Magnetics Societies (ICAUMS2012)   (奈良) 

    発表年月: 2012年10月

  • High temperature operation of diamond Schottky diodes above 750degree

    K. Ueda, K. Kawamoto, T. Soumiya, E. Bustarret, H. Asano

    International Conference on Solid State Devices and Materials(SSDM2012)   (京都) 

    発表年月: 2012年09月

  • 反強磁性ホイスラー合金Ru2MnGe薄膜の歪効果によるネール温度の上昇

    深谷直人, 藤田裕人, 宮脇哲也, 植田研二, 浅野秀文

    2012秋期第151回金属学会   (愛媛大学) 

    発表年月: 2012年09月

  • ハーフホイスラーLaPtBi薄膜の配向制御

    杉本望実, 新美陽平, 宮脇哲也, 深谷直人, 吉原健彦, 浅野秀文, 田中信夫

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • ホイスラー合金 / NbN接合の作製と電気的特性

    吉原健彦, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • ハーフメタル/Ba0.7Sr0.3TiO3/Fe2CrSi構造のマルチフェロイック特性

    川田浩憲, 小林耕平, 三宝勝利, 宮脇哲也, 植田研二, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • ダイヤモンド半導体/金属ショットキー接合の高温特性

    河本圭太, 植田研二, 宗宮嵩, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • 二重ペロブスカイトSrLaVRuO6の作製と磁気・伝導特性

    善戝良介, 松島宏行, 宮脇哲也, 植田研二, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • ハーフメタル/Ba0.7Sr0.3TiO3 ヘテロ構造の歪みとマルチフェロイック特性

    三宝勝利, 小林耕平, 宮脇哲也, 植田研二, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • 無限層構造 Sr1-xLaxCuO2

    赤塚寛之, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文

    2012秋季第73回応用物理学会学術講演会   (松山大学) 

    発表年月: 2012年09月

  • High-temperature characteristics of diamond Schottky diodes above 600°C

    K. Ueda, K. Kawamoto, T. Soumiya, H. Asano

    International Conference on Diamond and Carbon Materials(ICDCM2012)  

    発表年月: 2012年09月

  • Ferromagnetic Heusler/diamond heterostructures for spintronic applications

    K. Ueda, T. Soumiya, K. Kawamoto, N. Fukatani, H. Asano

    International Conference on Diamond and Carbon Materials(ICDCM2012)  

    発表年月: 2012年09月

  • Fabrication and Characterization of Heusler-alloy/Perovskite Heterostructures

    K. Kobayashi, K. Ueda, N. Fukatani, H. Kawada, K. Sakuma, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • Preparation and properties of inverse perovskite Mn3GaN thin films and heterostructures

    H. Tashiro, R. Suzuki, T. Miyawaki, K. Ueda, H. Asano

    ICM2012  

    発表年月: 2012年06月

  • Reactively sputtered MgAl2O4 barrier layers for Heusler tunnel junctions

    K. Inagaki, N. Fukatani, K. Mari, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    ICM2012  

    発表年月: 2012年06月

  • Structural and electrical properties of (111) oriented half-Heusler LaPtBi thin films

    N. Sugimoto, Y. Niimi, T. Miyawaki, T. Yoshihara, N. Fukatani, K. Ueda, N. Tanaka, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • Fabrication and properties of double perovskite SrLaVRuO6

    R. Zenzai, T. Miyawaki, K. Ueda, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • Inversion of magnetoresistance in La1-xSrxMnO3 /Nb-doped SrTiO3/CoFe junctions

    K. Ueda, K. Tozawa, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • Growth of a-axis oriented thin films of infinite-layer Sr1-xLaxCuO2

    H. Akatsuka, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • Structural and magnetic properties of antiferromagnetic Heusler Ru2MnGe epitaxial thin films

    N. Fukatani, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    ICM2012   (プサン) 

    発表年月: 2012年06月

  • X-ray photoelectron spectroscopy of half-Heusler La-Pt-Bi thin films

    N. Sugimoto, T. Miyawaki, Y. Niimi, T. Yoshihara, N. Fukatani, K. Ueda, N. Tanaka, H. Asano

    INTERMAG 2012   (バンクーバー) 

    発表年月: 2012年05月

  • Antiferromagnetic Heusler Ru2MnGe Epitaxial thin films showing Neel temperatures up to 353 K

    N. Fukatani, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    INTERMAG 2012   (バンクーバー) 

    発表年月: 2012年05月

  • Epitaxial thin films of ordered double perovskite SrLaVMoO6

    K. Sanbou, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano

    Materials Research Society (2012 MRS Spring Meeting)   (ボストン) 

    発表年月: 2012年04月

  • 超伝導NbN / 磁性接合の界面スピン分極率測定

    吉原健彦, 新野貴士, 北條貴之, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文

    平成23年度ナノネット報告会   (分子科学研究所) 

    発表年月: 2012年03月

  • 銅酸化物超伝導体Sr0.9La0.1CuO2薄膜の面内構造評価

    赤塚寛之, 作間啓太, 植田研二, 浅野秀文

    平成23年度ナノネット報告会   (分子科学研究所) 

    発表年月: 2012年03月

  • MgAl2O4障壁層を有する強磁性トンネル接合の結晶構造解析

    真利研一郎, 稲垣圭真, 藤田裕人, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    日本金属学会2012春期(第150回)大会   (横浜国立大学) 

    発表年月: 2012年03月

  • MgAl2O4障壁層を有する強磁性トンネル接合の結晶構造解析

    真利研一郎, 稲垣圭真, 藤田裕人, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    日本金属学会2012春期(第150回)大会   (横浜国立大学) 

    発表年月: 2012年03月

  • ホイスラー/強誘電体積層構造のマルチフェロイック特性

    小林 耕平, 鈴木 亮佑, 宮脇 哲也, 植田 研二, 浅野 秀文

    2012春季第59回応用物理学会   (早稲田大学) 

    発表年月: 2012年03月

  • 三元同時スパッタリング法によるLa-Pt-Bi薄膜の作製

    杉本 望実, 深谷 直人, 吉原 健彦, 宮脇 哲也, 植田 研二, 田中 信夫, 浅野 秀文

    2012春季第59回応用物理学会   (早稲田大学) 

    発表年月: 2012年03月

  • 中間層に酸化物半導体を用いた接合における 磁気抵抗効果と電気伝導メカニズム

    戸澤克倫, 植田研二, 作間 啓太, 小林耕平, 鈴木亮佑, 宮脇哲也, 浅野秀文

    2012春季第59回応用物理学会   (早稲田大学) 

    発表年月: 2012年03月

  • 二重交換相互作用による反強磁性ハーフメタルの発現

    三宝 勝利, 作間 啓太, 松島 宏行, 宮脇 哲也, 植田 研二, 浅野 秀文

    IEEE Magnetics Society 名古屋支部若手研究会   (名古屋大学) 

    発表年月: 2012年02月

  • 反応性スパッタを用いたFe2CrSi/MgAl2O4積層構造の作製

    深谷直人, 稲垣圭真, 真利研一郎, 藤田裕人, 宮脇哲也, 植田研二, 浅野秀文

    IEEE Magnetics Society 名古屋支部若手研究会   (名古屋大学) 

    発表年月: 2012年02月

  • Fabrication of Schottky junctions using diamond/ferromagnet heterostructures

    T. Soumiya, K. Ueda, H. Asano

    International Symposium on EcoTopia Science(ISETS)   (名古屋) 

    発表年月: 2011年12月

  • Growth of half-Heusler alloy LaPtBi thin films by 3-source magnetron sputtering

    N. Sugimoto, N. Fukatani, T. Yoshihara, T. Miyawaki, K. Ueda, N. Tanaka, H. Asano

    International Symposium on EcoTopia Science(ISETS)   (名古屋) 

    発表年月: 2011年12月

  • 格子整合系Fe2CrSi/MgAl2O4/Fe2CrSiトンネル接合の作製

    真利研一郎, 稲垣圭真, 藤田裕人, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    日本金属学会2011秋期(弟149回)大会   (沖縄) 

    発表年月: 2011年11月

  • Structural and electrical properties of half-Heusler LaPtBi thin films grown by 3-source magnetron co-sputtering

    T. Miyawaki, N. Sugimoto, N. Fukatani, T. Yoshihara, K. Ueda, N. Tanaka, H. Asano

    56th Annual Conference on Magnetism and Magnetic Materials (MMM2011)  

    発表年月: 2011年10月

  • Multiferroic properties in Heusler-alloy/perovskite layered structures

    K.Kobayashi, T.Miyawaki, K.Ueda, H.Asano

    56th Annual Conference on Magnetism and Magnetic Materials (MMM2011)  

    発表年月: 2011年10月

  • Electron-doped Sr1-xLaxCuO2 thin films grown on LaAlO3 substrates with and without BaxSr1-xTiO3 buffer layer

    K. Sakuma, H.Akatsuka, K. Ueda, H. Asano

    24th International Symposium on Superconductivity (ISS)  

    発表年月: 2011年10月

  • Fabrication of MgAl2O4 thin films on ferromagnetic Heusler alloy Fe2CrSi by reactive magnetron sputtering

    N. Fukatani, K. Inagaki, K. Mari, H. Fujita, T. Miyawaki, K. Ueda, H. Asano

    2011 International Conference on Solid State Devices and Materials(SSDM2011)   (名古屋) 

    発表年月: 2011年09月

  • Quasiparticle Tunneling Spectroscopy in Fe4N/MgO/NbN Junctions

    K. Sakuma, T. Hohjo, T. Miyawaki, K. Ueda, H. Asano, Y. Komasaki, M. Tsunoda

    2011 International Conference on Solid State Devices and Materials(SSDM2011)   (名古屋) 

    発表年月: 2011年09月

  • Magnetoresistance effects in La1-xSrxMnO3/Nb-SrTiO3/Co junctions

    K. Tozawa, K. Kobayashi, T. Miyawaki, K. Ueda, H. Asano

    2011 International Conference on Solid State Devices and Materials (SSDM2011)   (名古屋) 

    発表年月: 2011年09月

  • 反応性スパッタを用いたMgAl2O4積層構造の作製

    稲垣圭真, 真利研一郎, 藤田裕人, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    第35回日本磁気学会学術講演会   (新潟、朱鷺メッセ) 

    発表年月: 2011年09月

  • 逆ペロブスカイトMn3GaN薄膜の構造と電気的特性

    田代裕樹, 宮脇哲也, 植田研二, 浅野秀文

    第35回日本磁気学会学術講演会   (新潟、朱鷺メッセ) 

    発表年月: 2011年09月

  • ペロブスカイト/ホイスラー積層構造のマルチフェロイック特性

    小林耕平, 植田研二, 浅野秀文

    第35回日本磁気学会学術講演会   (新潟、朱鷺メッセ) 

    発表年月: 2011年09月

  • ダイヤモンド半導体を用いた強磁性ショットキー接合の作製

    宗宮 嵩, 深谷 直人, 宮脇 哲也, 植田 研二, 浅野 秀文

    第35回日本磁気学会学術講演会   (新潟、朱鷺メッセ) 

    発表年月: 2011年09月

  • Ferromagnetic Schottky junctions using diamond semiconductors

    K. Ueda, T.Soumiya, K.Tozawa, H. Asano

    Diamond2011   (Garmisch-Partenkirchen) 

    発表年月: 2011年09月

  • ホイスラー合金/MgAl2O4積層膜のコヒーレントエピタキシー

    藤田裕人, 真利研一郎, 稲垣 圭真, 深谷 直人, 宮脇 哲也, 植田 研二, 浅野 秀文

    2011秋季第72回応用物理学会   (山形大学) 

    発表年月: 2011年08月

  • BaxSr1-xTiO3格子整合バッファ層を用いた無限層Sr1-xLaxCuO2 薄膜の作製とその特性

    作間 啓太, 赤塚 寛之, 植田 研二, 浅野 秀文

    2011秋季第72回応用物理学会   (山形大学) 

    発表年月: 2011年08月

  • Inter-layer exchange coupling in Fe2CrSi/Fe2VSi multilayers fabricated on MgAl2O4 substrates

    T. Miyawaki, K. Takahashi, N. Fukatani, K. Ueda, H. Asano

    INTERMAG 2011   (台北) 

    発表年月: 2011年04月

  • Transport and local magnetic properties in strained Fe2VSi thin film

    N. Fukatani, K. Ueda, H. Asano, K.Mibu

    INTERMAG 2011   (台北) 

    発表年月: 2011年04月

  • 格子整合系MgAl2O4/ホイスラー合金積層構造の結晶構造評価

    宮脇哲也, 真利研一郎, 高橋一成, 藤田裕人, 深谷直人, 植田研二, 浅野秀文

    磁気記録・情報ストレージ研究会   (名古屋大学) 

    発表年月: 2011年03月

  • Spin polarization measurements in Fe4N/MgO/NbN tunnel junctions using quasiparticle tunneling spectroscopy

    T. Hohjo, K. Sakuma, T. Miyawaki, K. Ueda, H. Asano, Y. Komasaki, M. Tsunoda

    American Physical Society (2011 APS March Meeting)  

    発表年月: 2011年03月

  • 反強磁性ホイスラー合金Fe2VSi薄膜の歪効果と電気伝導特性

    深谷直人, 植田研二, 浅野秀文

    IEEE Magnetics Society 名古屋支部若手研究会   (名古屋大学) 

    発表年月: 2011年02月

  • 超伝導NbNを用いた強磁性Fe4Nのスピン分極率解析

    北條貴之, 作間啓太, 宮脇哲也, 植田研二, 浅野秀文, 駒崎洋亮, 角田匡清

    IEEE Magnetics Society 名古屋支部若手研究会   (名古屋大学) 

    発表年月: 2011年02月

  • BiFeO3系マルチフェロイック薄膜の極薄膜化とスピンフィルター素子への応用

    浅野秀文, 小林智, 立木翔治, 小林耕平, 宮脇哲也, 植田研二

    第12回金属/酸化物スピントロニクスセミナー   (東北大学) 

    発表年月: 2010年12月

  • Fabrication of semiconducting cubic boron nitride films on CVD diamond by ion-beam assisted sputtering

    K. Ueda, H. Asano

    Materials Research Society (2010 MRS Fall Meeting)  

    発表年月: 2010年11月

  • Epitaxial Bi0.75Ba0.25FeO3/Ba0.7Sr0.3TiO3 Structures for Multiferroic Junctions

    S. Tachiki, K. Yoshimoto, S. Kobayashi, T. Miyawaki, K. Ueda, H. Asano

    The 55th Magnetism and Magnetic Materials Conference  

    発表年月: 2010年11月

  • Fabrication and properties of double perovskite SrLaVMoO6 epitaxial thin films

    H. Matsushima, H. Gotoh, T. Miyawaki, K. Ueda, H. Asano

    The 55th Magnetism and Magnetic Materials Conference  

    発表年月: 2010年11月

  • ReBa2Cu307-8 Thin Films Grown on A-plane Sapphire Substrates with CeO2 Buffer Layers

    K. Sakuma, O. Michikami, K. Ueda, H. Asano

    23rd International Symposium on Superconductivity (ISS2010)   (エポカルつくば) 

    発表年月: 2010年11月

  • Fe2VSi薄膜の歪効果と電気伝導特性

    深谷直人, 植田研二, 浅野秀文

    第34回日本磁気学会学術講演会   (つくば国際会議場) 

    発表年月: 2010年09月

  • Fe2CrSi/Fe2VSi多層膜の磁気特性と磁気抵抗効果

    宮脇哲也, 高橋一成, 藤田裕人竹田陽一, 植田研二, 浅野秀文

    第34回日本磁気学会学術講演会   (つくば国際会議場) 

    発表年月: 2010年09月

  • ReBa2Cu307-8 Thin Films Grown on A-plane Sapphire Substrates with Oxide Buffer Layers

    K. Sakuma, K. Ueda, H. Asano, O. Michikami

    International Workshop on Oxide (WOE17)   (淡路夢舞台国際会議場) 

    発表年月: 2010年09月

  • Fabrication and physical properties of antiferromagnetic double perovskite compound Sr2-xLaxVMoO6

    K. Ueda, H. Matsushima, T. Hojiyo, H. Gotoh, T. Miyawaki, H. Asano

    International Workshop on Oxide (WOE17)   (淡路夢舞台国際会議場) 

    発表年月: 2010年09月

  • イオンビームアシストスパッタ法によるCVDダイヤモンド上への立方晶窒化ホウ素薄膜の作製

    植田研二, 浅野秀文

    2010秋季第71回応用物理学会   (長崎大学) 

    発表年月: 2010年09月

  • 半導体NbドープSrTiO3を中間層に持つ磁気抵抗効果素子の作製

    戸澤 克倫, 立木 翔治, 宮脇 哲也, 植田 研二, 浅野 秀文

    2010秋季第71回応用物理学会   (長崎大学) 

    発表年月: 2010年09月

  • マグネトロンスパッタリング法を用いた無限層超伝導 Sr1-xLaxCuO2薄膜のエピタキシャル成長

    作間啓太, 植田研二, 浅野秀文宮脇哲也

    2010秋季第71回応用物理学会   (長崎大学) 

    発表年月: 2010年09月

  • ダブルペロブスカイトSrLaVMoO6薄膜の作製と評価

    松島宏行, 後藤大尚, 松島宏行後藤大尚, 宮脇哲也, 植田研二浅野秀文

    2010秋季第71回応用物理学会  

    発表年月: 2010年09月

  • ハーフメタルFe2CrSi/MgAl2O4接合のヘテロエピタキシーとトンネル磁気抵抗効果

    藤田裕人, 真利研一郎, 深谷直人, 宮脇哲也, 植田研二, 浅野秀文

    2010秋季第71回応用物理学会   (長崎大学) 

    発表年月: 2010年09月

  • Carrier doping effects in the antiferromagnetic double perovskite Sr2-xLaxVMoO6

    T. Hohjo, H. Matsushima, H. Gotoh, Y. Takeda, K. Ueda, H. Asano

    International Symposium on Advanced Magnetic Materials and Applications (ISAMMA2010)   (仙台国際センター) 

    発表年月: 2010年07月

  • Bi0.75 Ba0.25FeO3/Ba0.7Sr0.3TiO3 bilayered structures for multiferroic tunnel junctions

    S. Tachiki, K. Yoshimoto, S. Kobayashi, Y. Takeda, K. Ueda, H. Asano

    International Symposium on Advanced Magnetic Materials and Applications (ISAMMA2010)   (仙台国際センター) 

    発表年月: 2010年07月

  • 反強磁性ホイスラー合金薄膜の歪み効果と電子構造

    深谷直人, 植田研二, 藤田裕人高橋一成, 竹田陽一, 浅野秀文

    第34回 日本磁気学会ナノマグネティクス専門研究会  

    発表年月: 2010年05月

  • ハーフメタル/Bi1-xBaxFeO3接合のスピンフィルター効果

    小林智, 吉本耕助, 立木翔治, 竹田陽一, 植田研二, 浅野秀文

    平成21年度中部地区ナノテク総合支援報告会  

    発表年月: 2010年05月

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現在担当している科目

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担当経験のある科目(授業)

  • 先端材料と物性物理

    名古屋大学  

  • 機能材料学

    名古屋大学  

  • 薄膜プロセス工学

    名古屋大学  

  • 量子力学1

    名古屋大学  

  • 先端材料と物性物理

    名古屋大学  

  • 機能材料学

    名古屋大学  

  • 薄膜プロセス工学

    名古屋大学  

  • 量子力学1

    名古屋大学  

  • スピン物性工学特論

    名古屋大学  

  • 結晶材料学基礎

    名古屋大学  

  • 物性物理学第4

    名古屋大学  

  • 基礎セミナー

    名古屋大学  

  • 化学基礎1

    名古屋大学  

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委員歴

  • 2014年04月
    -
    2022年03月

    日本応用物理学会  東海支部幹事

  • 2017年09月
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    2021年03月

    日本磁気学会  企画委員会委員

  • 2013年04月
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    2016年03月

    日本応用物理学会  APEX/JJAP編集委員

  • 2010年04月
    -
    2016年03月

    日本応用物理学会  JJAP編集委員

  • 2010年04月
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    2014年03月

    日本真空学会 SP部会(スパッタリング及びプラズマプロセス技術部会)  幹事

  • 2013年02月
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    2014年01月

    日本真空学会  東海支部幹事

  • 2011年04月
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    2013年03月

    SSDM国際会議論文委員会(エリア8)  論文委員

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