KASAHARA Kenji

    Department of Electric and Electronic Engineering Lecturer
Last Updated :2024/05/19

Researcher Information

Research funding number

  • 00706864

J-Global ID

Research Areas

  • Nanotechnology/Materials / Nanomaterials

Academic & Professional Experience

  • 2023/04 - Today  Kindai UniversityFaculty of Humanity-Oriented Science and Engineering Department of Electric and Electronic Engineering
  • 2015/04 - 2023/03  Fukuoka UniversityFaculty of Science Department of Applied Physics助教
  • 2013/04 - 2015/03  九州大学大学院システム情報科学研究院特任助教
  • 2011/04 - 2013/03  日本学術振興会 特別研究員(DC2)

Education

  • 2010/04 - 2013/03  Kyushu University  システム情報科学府  電気電子工学専攻
  • 2008/04 - 2010/03  Kyushu University  システム情報科学府  電子デバイス工学専攻
  • 2004/04 - 2008/03  Kyushu University  工学部  電気情報工学科

Association Memberships

  • 応用物理学会   日本磁気学会   

Published Papers

  • Taiga Hara; Kenji Kasahara; Takashi Manago
    Journal of Physics D: Applied Physics IOP Publishing 55 (36) 365001 - 365001 0022-3727 2022/09 [Refereed]
     
    Abstract Spin wave propagation in a magnonic crystal excited at a specific wavenumber was investigated by micromagnetic simulation modelling with meander-shaped antennae. The dispersion relation when excited at wave number k which corresponds to the boundary of the Brillouin zone, shows a pair of strong spots that originate from the magnonic upper and lower bands. When excited at wavenumber slightly offset from k above, additional strong spots appear and it shows intensity nonreciprocity reversal. It can be interpreted in terms of the repeated or reduced zone scheme of the Brillouin zone. These characteristics have the potential for novel control of nonreciprocity.
  • Propagation properties of MSSWs for the YIG mediums fabricated by a MOD method
    笠原健司; 中野貴文; 眞砂卓史
    福岡大学理学集報 52 (2) 47 - 51 2022/09
  • Takashi Manago; Kanta Fujii; Kenji Kasahara; Kazuyuki Nakayama
    Journal of Physics D: Applied Physics IOP Publishing 55 (11) 115005 - 115005 0022-3727 2022/03 [Refereed]
     
    Abstract The characteristics of spin waves (SWs) propagating in Fibonacci magnonic quasi-crystals (MQCs) were investigated in micromagnetic simulations. The SWs feel 1/3 of the characteristic Fibonacci sequence length as a period, and mini band gaps reflected by MQCs are formed. The effect of the MQC on the SW’s propagation becomes prominent above the first band gap frequency. The properties of SWs in MQCs generally depend on the propagation direction, because SWs feel different structures depending on the direction. Therefore, the nonreciprocity (NR) characteristics becomes complex. The NR characteristics change at every band gap frequency and hence across the frequency regions defined by them. In particular, some frequency regions have almost no NR, while others have enhanced NR and some have even negative NR. These characteristics seem to provide a new way to control NR.
  • Kenji Kasahara; Shingo Sueda; Takashi Manago
    AIP Advances AIP Publishing 12 (1) 015204 - 015204 2022/01 [Refereed]
  • K. Kasahara; R. Akamatsu; T. Manago
    AIP advances 11 (4) 045308 - (6 pages) 2021/04 [Refereed]
  • GeAu層を用いた金誘起相関交換成長法で作製した結晶性Geにおける結晶学的特性と電気伝導特性の評価
    MANAGO Takashi; KASAHARA Kenji
    Fukuoka University Science Reports 51 (1) 1 - 6 2021/03
  • T. Manago; K. Kasahara; I. Shibasaki
    AIP Advances 11 (3) 035213 - (6 pages) 2021/03 [Refereed]
  • T. Manago; M. M. Aziz; F. Ogrin; K. Kasahara
    J. Appl. Phys. AIP 126 (4) 043904 - (8 pages) 2019/06 [Refereed]
  • K. Kasahara; S. Wang; T. Ishibashi; T. Manago
    Jpn. J. Appl. Phys. 58 (6) 060906 - (4 pages) 2019/05 [Refereed]
  • K. Shibata; K. Kasahara; T. Manago
    Appl. Phys. Express 12 (5) 053002 - (4 pages) 2019/04 [Refereed]
  • K. Shibata; K. Kasahara; K. Nakayama; V. V. Kuruglyak; M. M. Aziz; T. Manago
    J. Appl. Phys. 124 (24) 243901 - (6 pages) 2018/12 [Refereed]
  • Takashi Manago; Kenji Kasahara; Kazuhiro Nishimura; Ichiro Shibasaki
    IEEJ Transactions on Sensors and Micromachines Institute of Electrical Engineers of Japan 138 (3) 117 - 122 1347-5525 2018 [Refereed]
     
    Magnetic sensor characteristics of InSb Hall element with a ferrite sandwich structure were investigated. This sensor can accurately measure a magnetic field of the order of 1 μT and the standard deviation of the measured magnetic field is about 130 nT. Fluctuation of the offset voltage and noise power spectrum was measured and 1/f noise was observed up to 10 kHz for applied current of 8 mA. It was also found that the noise power spectrum density was proportional to input current.
  • Kenji Kasahara; Hidenori Higashi; Mario Nakano; Yuta Nagatomi; Keisuke Yamamoto; Hiroshi Nakashima; Kohei Hamaya
    MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING ELSEVIER SCI LTD 70 68 - 72 1369-8001 2017/11 [Refereed]
     
    We examine electrical properties of pseudo-single-crystalline (PSC) Ge films, formed by modulated Au induced-crystallization (GIC) method, on glass substrates. Although higher growth temperatures and thicker Au layers in GIC conditions degrade the Hall mobility of holes, the influence of the Au deep centers can be ignored. For the thin film transistors, we find that post annealing in N-2 atmosphere enables us to enhance field-effect mobility and the on-off ratios. We discuss the mechanism of the improvement of electrical properties of the PSC-Ge films on the glass substrate. (C) 2016 Elsevier Ltd. All rights reserved. (C) 2016 Elsevier Ltd. All rights reserved.
  • Kenji Kasahara; Takashi Manago
    JAPANESE JOURNAL OF APPLIED PHYSICS IOP PUBLISHING LTD 56 (11) 110303 - (4 pages) 0021-4922 2017/11 [Refereed]
     
    We have succeeded in obtaining epitaxial yttrium-iron garnet (YIG) micropatterns on a gadolinium-gallium garnet (GGG) substrate by a metal-organic decomposition method with electron-beam (EB) irradiation. We have demonstrated that metal-octylates of Y and Fe showed negative exposure behavior for EB irradiation. X-ray diffraction measurements indicated that the YIG micropatterns were epitaxially well grown on a GGG(111) substrate. The magnetization curve of the YIG micropatterns showed a clear hysteresis loop and the saturation magnetization was estimated to be approximately 100 emu/cm(3), which is consistent with that of bulk YIG. (C) 2017 The Japan Society of Applied Physics
  • K. Kasahara; M. Nakayama; X. Ya; K. Matsuyama; T. Manago
    Jpn. J. Appl. Phys. Institute of Physics 56 (1) 010309 - (4 pages) 0021-4922 2016/12 [Refereed]
     
    We investigated the effect of the distance between a magnetic layer and an excitation antenna on the nonreciprocity of magnetostatic surface waves (MSSWs), using devices with various thicknesses of the SiO2layer (tSiO2) to isolate an antenna from a permalloy layer. The nonreciprocity of MSSWs increases with increasing tSiO2. This increase in MSSW nonreciprocity is caused by an increase in the ratio of the MSSW excitation efficiency of the out-of-plane component of a microwave field to that of the in-plane component of a microwave field. Thus, we found that the nonreciprocity of MSSWs can be controlled by a very simple method.
  • Spin wave propagation in a permalloy film under tangentially fields
    Kasahara Kenji; Masaki Nakayama; Mayuri Tashima; Sinya. Kasai; Manago Takashi
    Fukuoka University Science Reports 46 (2) 65 - 68 2016/08 [Refereed]
  • K. Hamaya; S. Yamada; K. Kasahara; T. Kanashima
    ECS Transactions Electrochemical Society Inc. 75 (8) 651 - 659 1938-6737 2016 [Refereed]
     
    Heteroepitaxial growth of bcc metallic alloys or a high-k insulator on Ge(111) has been explored for next generation Ge-based devices. First, we introduce a finely controlled crystal growth technique of bcc-type ferromagnetic alloys on Ge(111). Next, we show that the Fermi level pinning is significantly suppressed at the high-quality bcc-alloys/Ge heterointerfaces. Using these kinds of structures, we can achieve spin injection and detection in n-Ge. Finally, we present a new approach to gate-stack structures for Ge- MOSFET. Even a crystalline high-k insulator can be grown epitaxially on Ge(111) and a high-quality heterointerface can be achieved. Also, reasonable electrical characteristics are obtained. These finely controlled heterointerfaces will open a way for developing new technologies in next generation Ge-based devices with low power consumption.
  • K. Kasahara; Y. Nagatomi; K. Yamamoto; H. Higashi; M. Nakano; S. Yamada; D. Wang; H. Nakashima; K. Hamaya
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 107 (14) 142102-1  0003-6951 2015/10 [Refereed]
     
    By developing a low-temperature (<= 300 degrees C) fabrication process for the gate-stack structure on Ge(111), we study electrical properties of thin film transistors (TFTs) consisting of (111)-oriented pseudo-single-crystalline-gertnanium (PSC-Ge) channels on glass. Although the Hall mobility (mu(Hall) of p-type PSC-Ge layers reaches 210 cm(2)/V s and the gate-stack/Ge interface has low trap density, we observe field-effect-mobility (mu(FE)) fluctuation in the p-channel TFTs from 8.2 to 71 cm(2)/V s, depending on the thickness of the PSC-Ge layer. Considering the mu(FE) fluctuation and low I-on/I(of)f ratio in the p-TFTs, we infer the presence of defective Ge layers near the surface of the glass substrate. This study reveals that it is quite important for the high-performance p-Ge TFTs to improve the quality of the Ge layer near the surface of the glass substrate or to choose other materials with better Ge/substrate interface qualities. (C) 2015 AIP Publishing LLC.
  • H. Higashi; K. Kasahara; K. Kudo; H. Okamoto; K. Moto; J. -H. Park; S. Yamada; T. Kanashima; M. Miyao; I. Tsunoda; K. Hamaya
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 106 (4) 041902-1  0003-6951 2015/01 [Refereed]
     
    We demonstrate large-area (similar to 600 mu m), (111)-oriented, and high-crystallinity, i.e., pseudo-single-crystalline, germanium (Ge) films at 275 degrees C, where the temperature is lower than the softening temperature of a flexible substrate. A modulated gold-induced layer exchange crystallization method with an atomic-layer deposited Al2O3 barrier and amorphous-Ge/Au multilayers is established. From the Raman measurements, we can judge that the crystallinity of the obtained Ge films is higher than those grown by aluminum-induced-crystallization methods. Even on a flexible substrate, the pseudo-single-crystalline Ge films for the circuit with thin-film transistor arrays can be achieved, leading to high-performance flexible electronics based on an inorganic-semiconductor channel. (C) 2015 AIP Publishing LLC.
  • Jong-Hyeok Park; Kenji Kasahara; Kohei Hamaya; Masanobu Miyao; Taizoh Sadoh
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 104 (25) 252110-1  0003-6951 2014/06 [Refereed]
     
    High-carrier-mobility semiconductors on flexible-plastic are essential to realize flexible electronics. For this purpose, electrical properties of orientation-controlled large-grain Ge crystals on flexible-plastic directly formed by nucleation-controlled gold-induced-crystallization (GIC) are examined, and compared with those obtained by aluminum-induced-crystallization (AIC). The Ge crystals show p-type conductions. Here, hole concentrations are 2.2 x 10(17) and 5.8 x 10(20) cm(-3) for GIC-Ge and AIC-Ge, respectively, which are explained on the basis of the solubility of Au and Al in Ge. Thanks to the low hole concentration, GIC-Ge shows high hole mobility (160 cm(2) V-1 s(-1)) compared with AIC-Ge (37 cm(2) V-1 s(-1)). These demonstrate significant advantage of GIC to realize high-performance flexible-electronics. (C) 2014 AIP Publishing LLC.
  • Reliable reduction of Fermi-level pinning at atomically matched metal/Ge interfaces by sulfur treatment
    K. Kasahara; S. Yamada; T. Sakurai; K. Sawano; H. Nohira; M. Miyao; K. Hamaya
    Applied Physics Letters American Institute of Physics 104 (17) 172109-1  2014/05 [Refereed]
  • Kohei Hamaya; Gotaro Takemoto; Yuzo Baba; Kenji Kasahara; Shinya Yamada; Kentarou Sawano; Masanobu Miyao
    THIN SOLID FILMS ELSEVIER SCIENCE SA 557 (3) 382 - 385 0040-6090 2014/04 [Refereed]
     
    We have explored an effect of the interface resistance of Fe3Si/n(+) -Ge Schottky-tunnel contacts on spin accumulation created electrically in n-Ge. Using the Schottky-tunnel contacts with a relatively high interface resistance, we can clearly detect spin-accumulation signals in n-Ge even at room temperature, meaning that the use of highly resistive Schottky tunnel contacts is effective to electrically create large spin accumulation. Since such highly resistive source and drain electrodes are not available for next-generation Ge-based spintronic applications with ultra-low power consumption, the development of highly spin-polarized spin injectors such as half-metallic materials is essential from now on. (c) 2013 Elsevier B.V. All rights reserved.
  • Kenji Kasahara; Yuichi Fujita; Shinya Yamada; Kentarou Sawano; Masanobu Miyao; Kohei Hamaya
    Applied Physics Express Japan Society of Applied Physics 7 (3) 033002-1  1882-0786 2014 [Refereed]
     
    We show nonlocal spin transport in n-Ge-based lateral spin-valve devices with highly ordered CO2FeSi/n+-Ge Schottky tunnel contacts. Clear spin-valve signals and Hanle effect curves are demonstrated at low temperatures, indicating the generation, manipulation, and detection of pure spin currents in n-Ge. The obtained spin generation efficiency of ̃0.12 is about two orders of magnitude larger than that for a previously reported device with Fe/MgO tunnel barrier contacts. Considering the spin-related behavior with temperature evolution, we infer that it is necessary to simultaneously demonstrate a high spin generation efficiency and improve the quality of the transport channel to realize Ge-based spintronic devices. © 2014 The Japan Society of Applied Physics.
  • K. Hamaya; Y. Baba; G. Takemoto; K. Kasahara; S. Yamada; K. Sawano; M. Miyao
    JOURNAL OF APPLIED PHYSICS AMER INST PHYSICS 113 (18) 183713-1  0021-8979 2013/05 [Refereed]
     
    We study electrical spin injection and detection in n-Ge across Fe3Si/n(+)-Ge Schottky tunnel barriers. Spin-accumulation signals detected electrically by the three-terminal Hanle-effect measurements have large temperature dependence, and the spin signals disappear at around 200 K. We find that the temperature variation in the spin signals is strongly related to that in the interface resistance of the Fe3Si/n(+)-Ge contacts. We also observe marked reduction in nonlocal spin-valve signals with increasing temperature in the four-terminal device with almost the same Fe3Si/n(+)-Ge/n-Ge heterostructure. Note that the nonlocal spin signals depend on not only the measurement temperature but also on the electrical characteristics of the spin injector. Considering the results of three-terminal and four-terminal measurements, we conclude that temperature dependence of the spin signals in our Fe3Si/n(+)-Ge/n-Ge devices is governed by the electrical characteristics of the spin injector. This study means that it is necessary to consider the effective Schottky-tunnel contacts with the stability on temperature variations for next-generation Ge-based spintronic applications. (C) 2013 AIP Publishing LLC.
  • K. Hamaya; S. Yamada; G. Takemoto; K. Masaki; Y. Fujita; K. Kasahara; Y. Ando; K. Sawano; M. Miyao
    ECS Transactions 50 235 - 243 1938-5862 2012/12 [Refereed]
     
    We present two important technologies for silicon-germanium (SiGe) spintronics. First, we show high-quality epitaxial growth of bcc-type ferromagnetic alloys on Si or Ge with atomically controlled interfaces. Second, we establish electrical spin injection and detection across the high-quality interfaces in Si- or Ge-based devices. Combining these technologies with a metal-oxide semiconductor field-effect transistor structure, we can demonstrate room-temperature detection of spin accumulation and control the magnitude of the spin signals. These novel and interesting results are expected to build the basis of a key technology toward developing next-generation SiGe spintronic devices. © The Electrochemical Society.
  • Effect of the magnetic domain structure in the ferromagnetic contact on spin accumulation in silicon
    Y. Ando; S. Yamada; K. Kasahara; K. Sawano; M. Miyao; K. Hamaya
    Applied Physics Letters American Institute of Physics 101 (23) 232404-1  2012/12
  • Dependence of Schottky barrier height on the junction size of bcc-metal/n-Ge(111) contacts
    H. Yoshioka; K. Kasahara; T. Nishimura; S. Yamada; M. Miyao; K. Hamaya
    2012 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices 238  2012/06 [Refereed]
  • Spin accumulation created electrically in an n-type germanium channel using Schottky tunnel contacts
    K. Kasahara; Y. Baba; K. Yamane; Y. Ando; S. Yamada; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    Journal Of Applied Physics American Institute of Physics 111 (7) 07C503  2012/02 [Refereed]
  • Y. Ando; K. Kasahara; S. Yamada; Y. Maeda; K. Masaki; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    PHYSICAL REVIEW B AMER PHYSICAL SOC 85 (3) 035320  1098-0121 2012/01 [Refereed]
     
    We study temperature evolution of spin-accumulation signals obtained by the three-terminal Hanle-effect measurements in a nondegenerated silicon channel with a Schottky-tunnel-barrier contact. We find the clear difference in the temperature-dependent spin signals between spin-extraction and spin-injection conditions. In a spin-injection condition with a low bias current, the magnitude of spin signals can be enhanced despite the rise of temperature. For the interpretation of the temperature-dependent spin signals, it is important to consider the sensitivity of the spin detection at the Schottky-tunnel-barrier contact in addition to the spin diffusion in Si.
  • K. Kasahara; H. Yoshioka; Y. Tojo; T. Nishimura; S. Yamada; M. Miyao; K. Hamaya
    ECS Transactions The Electrochemical Society 50 (9) 223 - 229 1938-5862 2012 [Refereed]
     
    Using low-temperature molecular beam epitaxy (LTMBE), we demonstrate high-quality heterointerfaces consisting of CoFe alloys and germanium (Ge) with a good atomic matching at the (111) plane. Electrical properties of the atomically matched CoFe/p-Ge(111) junctions with the area of (S) < ~10 μm2 clearly show the suppression of the Fermi-level pinning (FLP) effect, similar to the features of the atomically matched Fe3Si/p- Ge(111) junctions with S < ~10 μm2 in our previous work. This means that the suppression of FLP is independent on a kind of metals. As a result, we conclude that the formation of the atomically matched metal/Ge interfaces with almost no defects is important to suppress FLP. © The Electrochemical Society.
  • K. Kasahara; S. Yamada; K. Sawano; M. Miyao; K. Hamaya
    PHYSICAL REVIEW B AMER PHYSICAL SOC 84 (20) 205301  2469-9950 2011/11 [Refereed]
     
    The physical origin of Fermi level pinning (FLP) at metal/Ge interfaces has been argued over a long period. Using the Fe3Si/Ge(111) heterostructure developed originally, we can explore electrical transport properties through atomically matched metal/Ge junctions. Unlike the conventional metal/p-Ge junctions reported so far, we clearly observe rectifying current-voltage characteristics with a measurable Schottky barrier height, depending on the contact area of the Fe3Si/Ge(111) junction. These results indicate that one should distinguish between intrinsic and extrinsic mechanisms for discussing the formation of the Schottky barrier at metal/Ge interfaces. This study will be developed for understanding FLP for almost all the metal/semiconductor interfaces.
  • Y. Ando; Y. Maeda; K. Kasahara; S. Yamada; K. Masaki; Y. Hoshi; K. Sawano; K. Izunome; A. Sakai; M. Miyao; K. Hamaya
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 99 (13) 132511  0003-6951 2011/09 [Refereed]
     
    We demonstrate spin accumulation signals controlled by the gate voltage in a metal-oxide-semiconductor field effect transistor structure with a Si channel and a CoFe/n(+)-Si contact at room temperature. Under the application of a back-gate voltage, we clearly observe the three-terminal Hanle-effect curves, i.e., spin accumulation signals. The magnitude of spin accumulation signals can be reduced with increasing the gate voltage. We consider that the gate controlled spin signals are attributed to the change in the carrier density in the Si channel beneath the CoFe/n(+)-Si contact. This study is not only a technological jump for Si-based spintronic applications with gate structures but also reliable evidence for the spin injection into the semiconducting Si channel at room temperature. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3643141]
  • Y. Ando; K. Kasahara; K. Yamane; Y. Baba; Y. Maeda; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 99 (1) 012113-1 - 012113-3 0003-6951 2011/07 [Refereed]
     
    We study the electrical detection of spin accumulation at a ferromagnet-silicon interface, which can be verified by measuring a Hanle effect in three-terminal lateral devices. The device structures used consist of a semiconducting Si channel and a Schottky tunnel contact. In a low current-bias region, the Hanle-effect curves are observed only under forward bias conditions. This can be considered that the electrical detectability at the forward-biased contact is higher than that at the reverse-biased contact. This is possible evidence for the detection of spin-polarized electrons created in a Si channel. (C) 2011 American Institute of Physics. [doi:10.1063/1.3607480]
  • K. Sawano; Y. Hoshi; K. Kasahara; K. Yamane; K. Hamaya; M. Miyao; Y. Shiraki
    Materials Research Society Symposium Proceedings 1305 30 - 36 0272-9172 2011 [Refereed]
     
    We demonstrate low-resistivity Ohmic contacts for n-Ge with ultra-shallow junction. Using the impurity δ-doping techniques with Ge homoepitaxy on Ge(111) below 400 °C, we can achieve a very abrupt doping profile within a nanometer-scale width. By introducing the δ-doping to atomically controlled metal/Ge contacts, the current-voltage characteristics clearly show Ohmic conductions owing to the effective tunneling through the Schottky barrier. This approach is promising for a formation technology of ultra-shallow source/drain contacts for scaled Ge devices. © 2011 Materials Research Society.
  • K. Sawano; Y. Hoshi; K. Kasahara; K. Yamane; K. Hamaya; M. Miyao; Y. Shiraki
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 97 (16) 162108-1  0003-6951 2010/10 [Refereed]
     
    We demonstrate ultrashallow Ohmic contacts for n-Ge by the Sb delta-doping and low-temperature Ge homoepitaxy. We find that the segregation effect of Sb on Ge (111) is lower than that on Ge (100) for growth temperatures below 400 degrees C. Consequently, we achieve the delta-doping for Ge (111), having very high concentrations above 10(20) cm(-3) and abrupt profiles within nanometer-scale widths. By introducing the delta-doping to atomically controlled metal/Ge Schottky contacts, completely symmetric current-voltage characteristics, that is, low-resistivity Ohmic contacts are obtained owing to the effective tunneling conduction through the Schottky barrier. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3503587]
  • Y. Ando; K. Kasahara; Y. Enomoto; T. Murakami; K. Hamaya; T. Kimura; K. Sawano; M. Miyao
    Journal of the Magnetic Society of Japan The Magnetic Society of Japan 34 (3) 316 - 322 1882-2924 2010/05 [Refereed]
     
    We investigated the epitaxial growth of high-quality Fe3Si thin films on Si(111) and demonstrated electrical injection and detection of spin-polarized electrons in Si through the Fe3Si/Si Schottky-tunnel contacts. TEM observations and analyses of electron diffraction patterns revealed that precisely controlling the Fe/Si ratio during growth is important to obtain well ordered Fe3Si structures and atomically abrupt heterointerfaces at the same time. The electrical properties of Fe3Si/Si Schottky diodes with various carrier concentrations were also examined, and highly transparent tunnel contacts were demonstrated. We were able to clearly detect nonlocal spin signals in Si at 150K using Fe3Si/Si lateral four-probe devices.
  • Highly ordered Co2FeSi Heusler alloys grown on Ge(111) by low-temperature molecular beam epitaxy
    K. Kasahara; K. Yamamoto; S. Yamada; T. Murakami; K. Hamaya; K. Mibu; M. Miyao
    Journal of Applied Physics American Institute of Physics 107 (9) 09B105  2010/04 [Refereed]
  • K. Yamane; K. Hamaya; Y. Ando; Y. Enomoto; K. Kasahara; K. Yamamoto; T. Sadoh; M. Miyao
    Appl. Phys. Lett. 96 162104-1 - 162104-3 2010 [Refereed]
  • Yuichiro Ando; Kenji Kasahara; Kazutaka Yamane; Kohei Hamaya; Kentarou Sawano; Takashi Kimura; Masanobu Miyao
    APPLIED PHYSICS EXPRESS JAPAN SOC APPLIED PHYSICS 3 (9) 093001-1  1882-0778 2010 [Refereed]
     
    We perform a detailed comparison of the nonlocal magnetoresistance (MR) curve with the local MR ones in Si-based lateral spin-valve devices with epitaxial ferromagnetic Fe3Si contacts, where the local MR originates from the anisotropic MR of the ferromagnetic contacts. We find that the nonlocal MR signals clearly depend on the magnetization reversal of the contacts, and they show positive or negative peak values when the magnetic configuration between two ferromagnetic contacts becomes nearly anti-parallel. These features mean that the obtained nonlocal MR signals can be distinguished from the suspicious signals, indicating a reliable result of the spin transport in Si. (c) 2010 The Japan Society of Applied Physics
  • Y. Ando; K. Hamaya; K. Kasahara; Y. Kishi; K. Ueda; K. Sawano; T. Sadoh; M. Miyao
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 94 (18) 182105-1  0003-6951 2009/05 [Refereed]
     
    We demonstrate electrical injection and detection of spin-polarized electrons in silicon (Si) using epitaxially grown Fe3Si/Si Schottky-tunnel-barrier contacts. By an insertion of a delta-doped n(+)-Si layer (similar to 10(19) cm(-3)) near the interface between a ferromagnetic Fe3Si contact and a Si channel (similar to 10(15) cm(-3)), we achieve a marked enhancement in the tunnel conductance for reverse-bias characteristics of the Fe3Si/Si Schottky diodes. Using laterally fabricated four-probe geometries with the modified Fe3Si/Si contacts, we detect nonlocal output signals that originate from the spin accumulation in a Si channel at low temperatures.
  • Y. Ando; K. Hamaya; K. Kasahara; K. Ueda; Y. Nozaki; T. Sadoh; Y. Maeda; K. Matsuyama; M. Miyao
    Journal of Applied Physics American Institute of Physics 105 (7) 07B102-1  0021-8979 2009 [Refereed]
     
    We study magnetic properties of epitaxial Fe3 Si layers grown on Ge(111) with atomically flat interfaces. An unexpected uniaxial magnetic anisotropy is observed in the film plane for all as-grown samples, and the direction of the uniaxial easy axis is different for each of these samples. By postgrowth annealing, surprisingly, the random orientation of the uniaxial easy axis is aligned to a direction along about [0 1- 1], together with a reduction in the saturation magnetization. We discuss a possible mechanism of the variation in the magnetic properties after the annealing. © 2009 American Institute of Physics.

Conference Activities & Talks

  • 準周期金属マグノニック結晶におけるスピン波伝搬特性
    藤井 幹太; 笠原 健司; 中山 和之; 眞砂 卓史
    第69回応用物理学会春季学術講演会  2022/03
  • MOD法で作製したエピタキシャルYIG薄膜の動的磁気特性の膜厚依存性
    笠原 健司; 末田真悟; 眞砂 卓史
    第69回応用物理学会春季学術講演会  2022/03
  • 非磁性金属層が静磁表面スピン波の緩和長に与える影響  [Not invited]
    薗畠 和真; 笠原 健司; 眞砂 卓史
    2021年第82回応用物理学会周期学術講演会  2021/09  オンライン  応用物理学会
  • Meander型アンテナで励起したマグノニック結晶中におけるMSSWの非相反性  [Not invited]
    原 大賀; 笠原 健司; 眞砂 卓史
    2021年第82回応用物理学会周期学術講演会  2021/09  オンライン  応用物理学会
  • InAsxSb1-x/AlyIn1-ySb量子井戸のバンド構造と極低温電子輸送特性  [Not invited]
    眞砂 卓史; 笠原 健司; 柴﨑一郎
    2020年第68回応用物理学会春季学術講演会  2021/03  オンライン  応用物理学会
  • 準周期マグノニック結晶を用いたMSSWの非相反性制御  [Not invited]
    藤井 幹太; 笠原 健司; 眞砂 卓史
    第44回日本磁気学会学術講演会  2020/12  オンライン  日本磁気学会
  • Magnonic band gaps of metallic one-dimensional magnonic crystals  [Not invited]
    眞砂 卓史; 笠原 健司
    第44回日本磁気学会学術講演会  2020/12  オンライン  日本磁気学会
  • 有機金属分解法で作製したYIG薄膜の動的磁気特性の結晶化温度依存性  [Not invited]
    笠原 健司; 眞砂 卓史
    2020年第81回応用物理学会秋季学術講演会  2020/09  オンライン  応用物理学会
  • Pt/Pyナノ狭窄構造を用いたスピントルク自励発振デバイスの作製  [Not invited]
    笠原 健司; 眞砂 卓史
    2020年第81回応用物理学会秋季学術講演会  2020/09  オンライン  応用物理学会
  • 電子線照射 MOD 法で作製した YIG パターンの動的磁化の評価  [Not invited]
    坂木 翔太; 笠原 健司; 眞砂 卓史
    2020年第67回応用物理学会春季学術講演会  2020/03  上智大学・四ッ谷キャンパス(東京)  応用物理学会
  • 非磁性金属層が強磁性金属層のダンピング定数に与える影響  [Not invited]
    赤松 竜成; 柴田 晃治; 笠原 健司; 眞砂 卓史
    2019年応用物理学会九州支部学術講演会  2019/11  熊本大学・黒髪キャンパス(熊本)  応用物理学会
  • GeAu同時蒸着金誘起層交換成長法で作製したGe薄膜の電気伝導特性  [Not invited]
    栫 昂輝; 笠原健司; 清水 昇; 角田 功; 眞砂卓史
    2019年応用物理学会九州支部学術講演会  2019/11  熊本大学・黒髪キャンパス(熊本)  応用物理学会
  • 単結晶InSbホール素子を用いたプリント配線中を流れる電流の非接触計測  [Not invited]
    笠原健司; 柴崎一郎; 眞砂卓史
    第36回「センサ・マイクロマシンと応用システム」シンポジウム  2019/11  アクトシティ浜松(浜松)  電気学会
  • 金属マグノニック結晶におけるマグノニックバンドギャップの電気的検出  [Not invited]
    笠原 健司; 柴田 晃治; 眞砂 卓史
    第88回ナノマグネッティクス専門研究会  2019/10  九州大学・西新プラザ(九州)  日本磁気学会
  • スピン波伝搬における導電性によるダンピング増大  [Not invited]
    眞砂 卓史; 笠原 健司; M; F. Azis; F. Ogrin; V. V. Kruglyak
    第88回ナノマグネッティクス専門研究会  2019/10  九州大学・西新プラザ(九州)  日本磁気学会
  • EB-MOD法で作製したBi置換YIG微細パターンの磁気光学効果  [Not invited]
    笠原 健司; 王 世浩; 石橋 隆幸; 眞砂 卓史
    2019年第80回応用物理学会秋季学術講演会  2019/09  北海道大学・札幌キャンパス  日本応用物理学会
  • 非磁性金属層がスピン波の拡散長に与える影響  [Not invited]
    赤松 竜成; 柴田 晃治; 笠原 健司; 眞砂 卓史
    2019年第80回応用物理学会秋季学術講演会  2019/09  北海道大学・札幌キャンパス  日本応用物理学会
  • 電子線照射MOD法を用いたSiO2/Si上へのBi:YIG微細パターンの作製  [Not invited]
    坂木 翔太; 笠原 健司; 眞砂 卓史
    2019年第80回応用物理学会秋季学術講演会  2019/09  北海道大学・札幌キャンパス  日本応用物理学会
  • Ge-Au 同時蒸着膜を用いた金誘起層交換成長法によるGe 結晶の低温形成  [Not invited]
    栫 昂輝; 笠原健司; 清水 昇; 角田 功; 眞砂卓史
    第66回応用物理学会春季学術講演会  2019/03  東京工業大学・大岡山キャンパス(東京)  日本応用物理学会
  • パーマロイマグノニック結晶を用いたアンテナ法によるマグノニックバンドギャップの電気的観測  [Not invited]
    柴田 晃治; 笠原 健司; 中山 和之; 眞砂 卓史
    第66回応用物理学会春季学術講演会  2019/03  東京工業大学・大岡山キャンパス(東京)  日本応用物理学会
  • マイクロマグネティックシミュレーションを用いたスピン波の伝搬特性における強磁性導波路幅依存性の検証  [Not invited]
    赤松 竜成; 柴田 晃治; 笠原 健司; 眞砂 卓史
    第66回応用物理学会春季学術講演会  2019/03  東京工業大学・大岡山キャンパス(東京)  日本応用物理学会
  • 電子線照射MOD法を用いたSiO2上へのGa:YIGサブミクロンパターンの作製  [Not invited]
    坂木 翔太; 笠原 健司; 眞砂 卓史
    第66回応用物理学会春季学術講演会  2019/03  東京工業大学・大岡山キャンパス(東京)  日本応用物理学会
  • GIC法におけるGeOx拡散制御層のGeの結晶成長に与える影響  [Not invited]
    栫 昂輝; 笠原健司; 清水 昇; 角田 功; 眞砂卓史
    第10回半導体材料・デバイスフォーラム  2018/10  熊本高等専門学校(熊本)
  • InSbホール素子を用いて測定した導線電流が作る磁場の距離依存性  [Not invited]
    笠原 健司; 眞砂 卓史
    第79回応用物理学会秋季学術講演会  2018/09  名古屋国際会議場  応用物理学会
  • 準周期接合界面におけるマグノン状態の研究  [Not invited]
    中山和之; 冨田知志; 川崎連; 笠原健司; 細糸信好; 柳久雄; 眞砂卓史
    第79回応用物理学会秋季学術講演会  2018/09  名古屋国際会議場  応用物理学会
  • Py導波路の幅がスピン波の伝搬特性に与える影響  [Not invited]
    赤松 竜成; 柴田 晃治; 笠原 健司; 眞砂 卓史
    第79回応用物理学会秋季学術講演会  2018/09  名古屋国際会議場  応用物理学会
  • サブミクロンサイズのCoドットを埋め込んだPy中を伝搬するスピン波の伝搬特性  [Not invited]
    柴田 晃治; 笠原 健司; 中山 和之; 眞砂 卓史
    第79回応用物理学会秋季学術講演会  2018/09  名古屋国際会議場  応用物理学会
  • 電子線照射MOD法を用いたSiO2上のGa:YIG微細パターンの作製  [Not invited]
    坂木 翔太; 笠原 健司; 眞砂 卓史
    第79回応用物理学会秋季学術講演会  2018/09  名古屋国際会議場  応用物理学会
  • Spin-wave Localization with Quasi-periodic Magnonic Metamaterials  [Not invited]
    K. Nakayama; S. Tomita; R. Kawasaki; K. Kasahara; N. Hosoito; H.Yanagi; T. Manago
    12th International Congress Metamaterials  2018/08  Espoo (Finland)
  • Antenna configuration dependence of nonreciprocity of spin waves  [Not invited]
    K. Shibata; K. Kasahara; K. Nakayama; V. V. Kruglyak; M. M. Aziz; T. Manago
    IEEE International Conference on Microwave Magnetics 2018  2018/06  Exeter (UK)
  • 準周期グレーティングによる静磁表面波の局在化  [Not invited]
    中山和之; 冨田知志; 川崎連; 笠原健司; 細糸信好; 柳久雄; 眞砂卓史
    日本物理学会第73回年次大会  2018/03  東京理科大学・野田キャンパス  日本物理学会
  • 電子線照射有機金属分解法によるBi 置換YIG 微細パターンの作製  [Not invited]
    KASAHARA Kenji; MANAGO Takashi
    第65回応用物理学会春季学術講演会  2018/03  早稲田大学・西早稲田キャンパス  応用物理学会
  • 磁性体準周期グレーティング構造の作製とスピン波測定  [Not invited]
    川崎 連; 中山 和之; 冨田知志; 笠原 健司; 眞砂 卓史; 細糸信好; 柳久雄
    第65回応用物理学会春季学術講演会  2018/03  早稲田大学・西早稲田キャンパス  応用物理学会
  • ホール素子による微小磁場計測の検討  [Not invited]
    眞砂 卓史; 笠原 健司; 西村 和浩; 柴崎 一郎
    第34回「センサ・マイクロマシンと応用システム」シンポジウム  2017/11  広島国際会議場(広島)  電気学会
  • マイクロマグネティックシミュレーションによる静磁表面スピン波の非相反性の検討  [Not invited]
    柴田 晃治; 笠原 健司; 中山 和之; 眞砂 卓史
    第78回応用物理学会秋季学術講演会  2017/09  福岡国際会議場(福岡)  応用物理学会
  • フィボナッチ格子を持つマグノニック結晶のスピン波特性  [Not invited]
    中山 和之; 冨田 知志; 笠原 健司; 諏訪 智巳; 細糸 信好; 柳 久雄; 眞砂 卓史
    第78回応用物理学会秋季学術講演会  2017/09  福岡国際会議場  応用物理学会
  • 電子線照射有機金属分解法による YIG微細パターンの作製  [Not invited]
    笠原 健司; 香野 淳; 眞砂 卓史
    第78回応用物理学会秋季学術講演会  2017/09  福岡国際会議場(福岡)  応用物理学会
  • Antenna Configuration Dependence of the Nonreciprocity of Magnetostatic Surface Wave  [Not invited]
    K. Shibata; K. Kasahara; K. Nakayama; T. Manago
    SPINTECH 9  2017/06  Fukuoka, Japan
  • 準周期磁気構造体を利用したスピン波制御  [Not invited]
    中山 和之; 冨田 知志; 笠原 健司; 児玉 俊之; 細糸 信好; 柳 久雄; 眞砂 卓史
    日本物理学会第72回年次大会  2017/03  大阪大学 (大阪)  日本物理学会
  • 静磁表面スピン波の非相反性におけるアンテナ形状依存性  [Not invited]
    柴田 晃治; 笠原 健司; 眞砂 卓史
    第64回応用物理学会春季学術講演会  2017/03  パシフィコ横浜(横浜)  応用物理学会
  • InSb薄膜ホール素子による微小磁場計測  [Not invited]
    眞砂 卓史; 笠原 健司; 柴崎 一郎
    第64回応用物理学会春季学術講演会  2017/03  パシフィコ横浜(横浜)  応用物理学会
  • Finely controlled heterointerfaces between Ge(111) and metallic alloys or insulators for next generation Ge-based devices  [Not invited]
    K. Hamaya; S. Yamada; K. Kasahara; T. Kanashima
    PRiME 2016/230th ECS Meeting  2016/10  Honolulu
  • Control of the nonreciprocity of magnetostatic surface wave in a ferromagnetic metal  [Not invited]
    笠原健司; 牙暁瑞; 松山公秀; 眞砂卓史
    第77回応用物理学会秋季学術講演会  2016/09  新潟  日本応用物理学会
  • Control of the nonreciprocity of magnetostatic surface wave in a ferromagnetic metal  [Not invited]
    笠原健司; 牙暁瑞; 松山公秀; 眞砂卓史
    第77回応用物理学会秋季学術講演会  2016/09  新潟  日本応用物理学会
  • Effect of post annealing on hole mobility of pseudo-single-crystalline germanium thin-film-transistors on glass substrates  [Not invited]
    K. Kasahara; H. Higashi; M. Nakano; Y. Nagatomi; K. Yamamoto; H. Nakashima; K. Hamaya
    ISTDM2016  2016/06  Nagoya
  • 静磁表面スピン波の非相反性に対するアンテナー磁性層間の距離依存性  [Not invited]
    中山 真伎; 笠原 健司; 眞砂 卓史
    第63回応用物理学会春季学術講演会  2016/03  東工大(東京)  日本応用物理学会
  • Pyに中間層を挿入した膜における静磁表面波の減衰長の関係  [Not invited]
    太田雅己; 葛西伸哉; 三谷誠司; 笠原健司; 眞砂卓史
    第63回応用物理学会春季学術講演会  2016/03  神奈川  日本応用物理学会
  • 静磁表面スピン波の非相反性に対するアンテナ-磁性層間の距離依存性  [Not invited]
    中山真伎; 笠原健司; 眞砂卓史
    第63回応用物理学会春季学術講演会  2016/03  神奈川
  • Pyに中間層を挿入した膜における静磁表面波の減衰長の関係  [Not invited]
    太田雅己; 葛西伸哉; 三谷誠司; 笠原健司; 眞砂卓史
    第63回応用物理学会春季学術講演会  2016/03  神奈川  日本応用物理学会
  • High hole mobility in pseudo-single-crystalline germanium films on flexible substrates  [Not invited]
    H. Higashi; M. Nakano; K. Kasahara; S. Yamada; T. Kanashima; K. Hamaya
    2016 MRS Spring Meeting  2016/03  Phoenix
  • 300℃以下プロセスで作製した結晶性GeチャネルTFT  [Not invited]
    笠原健司; 永冨雄太; 山本圭介; 東英実; 中野茉莉央; 山田晋也; 中島寛; 浜屋宏平
    第62回応用物理学会春季学術講演会  2015/03  神奈川
  • 金誘起層交換成長法で作成した擬似単結晶Geの電気伝導特性  [Not invited]
    中野茉莉央; 東英実; 笠原健司; 山田晋也; 金島岳; 浜屋宏平
    第62回応用物理学会春季学術講演会  2015/03  神奈川
  • フレキシブル基板上への擬似単結晶Ge薄膜の形成  [Not invited]
    東英実; 笠原健司; 工藤康平; 岡本隼人; 茂藤健太; パクジョンヒョク; 山田晋也; 金島岳; 宮尾正信; 角田功; 浜屋宏平
    第62回応用物理学会春季学術講演会  2015/03  神奈川
  • Generation and detection of pure spin current in n-Ge using L21-ordered Co2FeSi electrodes  [Not invited]
    K. Kasahara; Y. Fujita; S. Yamada; K. Sawano; M. Miyao; K. Hamaya
    Intermag 2014  2014/05  Dresden
  • 層交換法による大粒径Ge結晶/プラスチックの直接成長ーフレキシブル基板上における高移動度の実現ー  [Not invited]
    朴ジョンヒョク; 笠原健司; 浜屋宏平; 宮尾正信; 佐道泰造
    第61回応用物理学会春季学術講演会  2014/03  神奈川
  • High efficient detection of pure spin currents in n-Ge using L21-Co2FeSi Heusler-compound electrodes  [Not invited]
    藤田裕一; 笠原健司; 山田晋也; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第61回応用物理学会春季学術講演会  2014/03  神奈川
  • Co2FeSiホイスラー合金電極を用いたn型Ge中のスピン伝導検出  [Not invited]
    笠原健司; 藤田裕一; 山田晋也; 澤野憲太郎; 宮尾正信; 浜屋宏平
    The 18th Symposium on the Physics and Applications of Spin-related Phenomena in Semiconductors  2013/12  大阪
  • Effect of an atomically matched structure on Fermi-level pinning at metal/p-Ge interfaces  [Not invited]
    K. Kasahara; H. Yoshioka; S. Yamada; T. Nishimura; M. Miyao; K. Hamaya
    222nd ECS Meeting  2012/10  Honolulu
  • Effect of an atomically matched structure on Fermi-level pinning at CoFe/p-Ge interfaces  [Not invited]
    H. Yoshioka; K. Kasahara; T. Nishimura; S. Yamada; M. Miyao; K. Hamaya
    IUMRS-ICEM2012  2012/09  Yokohama
  • Room temperature detection of spin accumulation created in n-Ge through Schottky tunnel contacts  [Not invited]
    G. Takemoto; Y. Baba; Y. Fujita; S. Yamada; K. Kasahara; Y. Hoshi; K.Sawano; M. Miyao; K. Hamaya
    The 7th International Conference on Physics and Applications of Spin-related Phenomena in Semiconductors  2012/08  Netherlands
  • Dependence of Schottky barrier height on the junction size of bcc-metal/n-Ge(111) contacts  [Not invited]
    H. Yoshioka; K. Kasahara; T. Nishimura; S. Yamada; M. Miyao; K. Hamaya
    AWAD 2012  2012/06  Okinawa
  • Marked suppression of the Fermi-level pinning at metal/Ge(111) junctions with atomically matched interfaces  [Not invited]
    K. Kasahara; S. Yamada; M. Miyao; K. Hamaya
    Materials Research Society 2012  2012/04  San Francisco
  • Room-temperature spin injection into Si in a metal-oxide-semiconductor field effect transistor structure with a high-quality Schottky-tunnel contact  [Not invited]
    Y. Ando; K. Masaki; K. Kasahara; S. Yamada; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    Materials Research Society 2012  2012/04  San Francisco
  • CoFe/Si界面の局在準位におけるスピン蓄積信号の検出  [Not invited]
    安藤裕一郎; 真崎紘平; 笠原健司; 山田晋也; 宮尾正信; 浜屋宏平
    第59回応用物理学関係連合講演会  2012/03  東京
  • Si-MOSFET構造におけるスピン蓄積の検出  [Not invited]
    真崎紘平; 安藤裕一郎; 前田雄也; 笠原健司; 山田晋也; 星 裕介; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第59回応用物理学関係連合講演会  2012/03  東京
  • Fe3Si/n+-Ge/n-Ge素子におけるスピン蓄積の生成・検出  [Not invited]
    竹本剛太郎; 馬場雄三; 笠原健司; 山田晋也; 星 裕介; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第59回応用物理学関係連合講演会  2012/03  東京
  • Electrical creation and detection of the spin accumulation in an n-Ge channel using Schottky tunnel contacts  [Not invited]
    G. Takemoto; Y. Baba; K. Kasahara; S. Yamada; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    The 38th Special Meeting of Special Session for Spintronics  2012/01  Osaka
  • Room-temperature detection of the spin-accumulation signals in a Si-MOSFET structure  [Not invited]
    K. Masaki; Y. Ando; Y. Maeda; K. Kasahara; S. Yamada; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    The 38th Special Meeting of Special Session for Spintronics  2012/01  Osaka
  • Electrical creation of spin accumulation in a Si channel using a Schottky tunnel contact  [Not invited]
    Y. Ando; Y. Maeda; K. Kasahara; S. Yamada; M. Miyao; K. Hamaya
    56th MMM 2011  2011/10  Arizona
  • Spin accumulation created electrically in an n-Ge channel using Schottky tunnel contacts  [Not invited]
    Y. Baba; K. Kasahara; K. Masaki; Y. Ando; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    56th MMM 2011  2011/10  Arizona
  • 三端子Hanle効果測定法を用いたSi中のスピン蓄積の検出  [Not invited]
    真崎紘平; 安藤裕一郎; 前田雄也; 笠原健司; 星 裕介; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第35回日本磁気学会学術講演会  2011/09  新潟
  • n-Ge中に生成されたスピン蓄積の検出  [Not invited]
    馬場雄三; 笠原健司; 真崎紘平; 安藤裕一郎; 星 裕介; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第35回日本磁気学会学術講演会  2011/09  新潟
  • Marked Suppression of the Fermi-level Pinning at Atomically Matched Fe3Si/p-Ge(111) Contacts  [Not invited]
    K. Kasahara; S. Yamada; M. Miyao; K. Hamaya
    SSDM 2011  2011/09  Nagoya
  • Electrical detection of spin accumulation in Ge through a Schottky tunnel barrier  [Not invited]
    K. Kasahara; Y. Baba; K. Yamane; Y. Ando; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    SPINTECH-6  2011/08  Matsue
  • Electrical detection of spin accumulation in silicon through a Schottky tunnel barrier  [Not invited]
    Y. Ando; K. Kasahara; K. Yamane; Y. Baba; Y. Maeda; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    SPINTECH-6  2011/08  Matsue
  • Suppression of Fermi-level pinning at atomically controlled Fe3Si/p-Ge(111) junctions  [Not invited]
    K. Kasahara; K. Yamane; Y. Baba; M. Miyao; K. Hamaya
    ICSI-7  2011/08  Leuven
  • Electrical detection of spin accumulation in Si with a high-quality CoFe/Si Schottky tunnel contact  [Not invited]
    Y. Maeda; Y. Ando; K. Kasahara; Y. Baba; M. Miyao; K. Hamaya
    2011 International Workshop on Advanced Electrical Engineering and Related Topics  2011/07  Bochum
  • Hanle measurements for accumulated spins in a silicon channel using a Schottky tunnel contact  [Not invited]
    Y. Ando; K. Kasahara; Y. Yamane; Y. Baba; Y. Maeda; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    5th International Workshop on Spin Currents  2011/07  Sendai
  • Three-terminal spin detection in Ge through a Schottky tunnel barrier  [Not invited]
    Y. Baba; K. Kasahara; K. Yamane; Y. Ando; Y. Hoshi; K. Sawano; M. Miyao; K. Hamaya
    5th International Workshop on Spin Currents  2011/07  Sendai
  • ハンル効果測定を用いた強磁性合金/シリコン界面近傍におけるスピン蓄積の電気的検出  [Not invited]
    安藤裕一郎; 笠原健司; 山根一高; 馬場雄三; 前田雄也; 星 裕介; 澤野憲太郎; 宮尾正信; 浜屋宏平
    第58回応用物理学関係連合講演会  2011/03  神奈川
  • Formation of ultra-shallow Ohmic contacts on n-Ge by Sb δ-doping  [Not invited]
    K. Sawano; Y. Hoshi; K. Kasahara; K. Yamane; K. Hamaya; M. Miyao; Y. Shiraki
    2010 MRS Fall Meeting  2010/11  Boston
  • Geへのスピン注入を目指したFe3Si/Ge界面の伝導制御  [Not invited]
    山根一高; 笠原健司; 浜屋宏平; 澤野憲太郎; 宮尾正信
    第34回日本磁気学会学術講演会  2010/09  筑波
  • Nonlocal detection of spin transport in silicon using a Co/Fe3Si injector and an Fe3Si detector  [Not invited]
    Y. Ando; K. Kasahara; K. Yamane; K. Hamaya; K. Sawano; T. Kimura; M. Miyao
    PASPS-Ⅵ  2010/08  Tokyo
  • Spin Injection into Si across an Fe3Si/Si Schottky-Tunnel Barrier  [Not invited]
    K. Hamaya; Y. Ando; K. Kasahara; S. Yamada; K. Yamane; T. Murakami; M. Miyao
    ISTESNE 2010  2010/06  Tokyo
  • 低抵抗コンタクト形成へ向けたGeへのSbデルタドーピングとその偏析現象  [Not invited]
    澤野憲太郎; 星裕介; 笠原健司; 山根一高; 浜屋宏平; 宮尾正信; 白木靖寛
    第57回応用物理学関係連合講演会  2010/03  湘南
  • Fe3Si/Siショットキー障壁を介したSiへの電気的スピン注入・検出  [Not invited]
    笠原健司; 安藤裕一郎; 浜屋宏平; 木村 崇; 澤野憲太郎; 宮尾正信
    第57回応用物理学関係連合講演会  2010/03  湘南
  • Nonlocal voltage detection of spin transport in silicon using Fe3Si/Si Schottky tunnel contacts  [Not invited]
    Y. Ando; K. Kasahara; Y. Enomoto; K. Yamane; K. Hamaya; K. Sawano; T. Kimura; M. Myao
    11th Joint MMM-Intermag Conference  2010/01  Washington
  • Fe3Si/Ge(111) Schottky contacts for spin injection into a Ge channel  [Not invited]
    K. Kasahara; Y. Ando; K. Yamane; Y. Enomoto; K. Sawano; K. Hamaya; M. Myao
    11th Joint MMM-Intermag Conference  2010/01  Washington
  • Highly epitaxial growth and its ferromagnetic properties of Heusler-alloy Co3-xFexSi/Ge(111) layers with an atomically flat heterointerface  [Not invited]
    K. Kasahara; K. Yamamoto; S. Yamada; T. Murakami; K. Hamaya; M. Miyao
    11th Joint MMM-Intermag Conference  2010/01  Washington
  • High-quality Co2FeSi/Si(111) heterointerfaces for spin injection into Si  [Not invited]
    S. Yamada; Y. Enomoto; K. Kasahara; T. Murakami; K, Yamane; K. Yamamoto; Y. Ando; K. Hamaya; M. Miyao
    5th International WorkShop on New Group IV Semiconductor Nanoelectronics  2010/01  Sendai
  • Spin injection into Si channels through Fe3Si/Si Schottky tunnel barriers  [Not invited]
    K. Kasahara; Y. Ando; Y. Enomoto; K. Yamane; K. Sawano; K. Hamaya; M. Myao
    5th International WorkShop on New Group IV Semiconductor Nanoelectronics  2010/01  Sendai
  • シリコン横型スピン伝導素子におけるFe3Si/Siショットキー接合を用いた非局所抵抗および局所抵抗の測定  [Not invited]
    山根一高; 安藤裕一郎; 笠原健司; 榎本雄志; 山本健士; 浜屋宏平; 澤野憲太郎; 木村崇; 宮尾正信
    第14回半導体スピン工学の基礎と応用  2009/12  東京
  • Atomically Controlled Epitaxial Growth of Ferromagnetic Heusler Alloys for SiGe Based Spintronics  [Not invited]
    M. Miyao; K. Hamaya; K. Kasahara; S. Yamada; K. Sawano
    SiNEP-09  2009/11  Spain
  • Epitaxial Full-Heusler-Alloy Co2FeSi Thin Films on Silicon for Si-based Semiconductor Spintronics  [Not invited]
    S. Yamada; Y. Enomoto; K. Kasahara, K; Yamane; K. Yamamoto; Y. Ando; K. Hamaya; M. Miyao
    2009 MRS Fall Meeting  2009/11  Boston
  • Spin-injection from epitaxially grown ferromagnetic Heusler alloys for SiGe based spin-transistor  [Not invited]
    M. Miyao; K. Hamaya; T. Sadoh; Y. Ando; K. Kasahara; S. Yamada
    ISANN 2009  2009/11  Maui
  • ショットキー障壁を介したシリコンへのスピン注入とその電気的検出  [Not invited]
    笠原健司; 安藤裕一郎; 浜屋宏平; 木村崇; 澤野憲太郎; 宮尾正信
    第70回応用物理学会学術講演会  2009/09  富山
  • SiGeスピントロニクス素子を目指したFe3Si/Ge構造の高品質形成  [Not invited]
    村上達彦; 上田公二; 安藤裕一郎; 笠原健司; 浜屋宏平; 壬生 攻; 佐道泰造; 宮尾正信
    第70回応用物理学会学術講演会  2009/09  富山
  • Fe3Si/Siショットキー障壁を介したスピン注入の電気的検出  [Not invited]
    安藤裕一郎; 笠原健司; 榎本雄志; 浜屋宏平; 木村崇; 澤野憲太郎; 宮尾正信
    第33回日本磁気学会学術講演会  2009/09  長崎
  • Magnetic properties of epitaxial Fe3Si/Ge(111) layers for group-IV semiconductor spintronic applications  [Not invited]
    Y. Ando; K. Kasahara; K. Ueda; K. Hamaya; Y. Nozaki; T. Sadoh; Y. Maeda; K. Matsuyama; M. Miyao
    SSDM 2008  2009/09  Tsukuba
  • Magnetic properties of epitaxially-grown Fe3Si/Ge(111) layers with atomically flat interfaces  [Not invited]
    Y. Ando; K. Kasahara; K. Ueda; K. Hamaya; Y. Nozaki; T. Sadoh; Y. Maeda; K. Matsuyama; M. Miyao
    53rd MMM2008  2008/11  Texas
  • Fe3Si /Ge(111)ヘテロ構造の磁気特性におけるアニール効果  [Not invited]
    笠原健司; 安藤裕一郎; 上田公二; 能崎幸雄; 松山公秀; 浜屋宏平; 佐道泰造; 前田佳均; 宮尾正信
    第69回応用物理学会学術講演会  2008/09  名古屋
  • Ge(111)上にエピタキシャル成長したFe3Si薄膜の磁気特性とそのアニール効果  [Not invited]
    安藤裕一郎; 上田公二; 笠原健司; 浜屋宏平; 能崎幸雄; 松山公秀; 佐道泰造; 宮尾正信
    第32回日本磁気学会学術講演会  2008/09  仙台

MISC

Industrial Property Rights

Awards & Honors

  • 2010 日本磁気学会 論文賞
     高品質Fe3Si/Siからなるショットキートンネル電極を用いた シリコン中のスピン伝導の電気的検出 
    受賞者: 安藤 裕一郎;笠原 健司;榎本 雄志;村上 達彦;浜屋 宏平;木村 崇;澤野 憲太郎;宮尾 正信
  • 2009 第27回(2009年秋季) 応用物理学会講演奨励賞

Research Grants & Projects

  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    Date (from‐to) : 2022/04 -2025/03 
    Author : 眞砂 卓史; 笠原 健司
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2022/04 -2025/03 
    Author : 笠原 健司
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    Date (from‐to) : 2020/04 -2023/03 
    Author : 浅井 祥仁; 稲田 聡明; 中山 和之; 笠原 健司; 中西 俊博; 久門 尚史; 冨田 知志; 澤田 桂
     
    ブラックホール時空の幾何学的性質を特殊な物性系の分散構造により再現し、そのホライゾンで生じるHawking輻射等の量子過程の研究が進んでいる。具体的には、これまで、87Rb BEC系のフォノンを用いた実験や誘電体中の光カー効果を用いた実験、および流体におけるdeep waveを用いた実験等が行われている。またスピン波マグノン系では天体ブラックホールよりも高いHawking温度の実現が可能である。そこで本研究ではこれら従来の系およびそれに該当しない新たな系に対し、ブラックホールの量子性に関する足がかりとなる知見を得ることを目的とする。 本年度では、従来よりも高いホーキング温度を持つ強磁性体-スピン波系を用いてBHの時空構造を実現しその量子的ふるまいを調べるために、測定系の構築およびテストサンプルの作製を行い、狭窄構造を変化させた際のスピン波応答を系統的に調査した。 また並行してGPUを用いた数値シミュレーションを進めており、3次元有限差分計算(FDM)の結果を日本物理学会に発表した。
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2022/03 
    Author : Manago Takashi
     
    InAs0.1Sb0.9/Al0.1In0.9Sb quantum wells with almost 0% lattice mismatch maintain conductivity and exhibit high mobility even at extremely low temperatures. When the band diagram of the quantum well structure was calculated, it was found that the band structure changed significantly depending on the composition of the well layer and barrier layers. Therefore, we systematically investigated the changes in the quantum well structure when the compositions of the well and barrier layers were changed, and proceeded with the development of a practical high-sensitivity magnetic sensor over a wide temperature range. We evaluated the band gaps, temperature dependence of the carrier density, the well confinement depth, and determined the optimum composition for high-sensitive magnetic sensors that can operate at extremely low temperatures.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2022/03 
    Author : Kasahara Kenji
     
    In this research, we improved the multi-layer gold-induced layer exchange growth (ML-GIC) method, which is developed by the principal investigator, and tried to reduce the hole concentration caused by defects in the Ge crystal film for aiming at low-temperature formation of n-type Ge crystals. Instead of the (a-Ge / Au) x multilayer structure used in the conventional ML-GIC method, an a-Ge layer doped Au , namely a GeAu layer, was used. Even in GIC using the GeAu layer, the formation of a (111) oriented Ge crystal layer was confirmed by X-ray diffraction and electron backscatter spectroscopy methods. However, the size of the Ge grains is about 120 um, which is about 1/8 times as large as that for the conventional ML-GIC method, and the hole concentration also increases due to the increase in grain boundaries caused by the decrease in crystal size.
  • 強磁性絶縁体を用いたゲルマニウム中への純スピン流生成技術の開発
    日本学術振興会:
    Date (from‐to) : 2016 -2017 
    Author : 笠原健司
  • 金属ソース・ドレイン型ゲルマニウムスピンMOSFETの創製
    日本学術振興会:
    Date (from‐to) : 2013 -2014
  • 室温動作スピントランジスタの創製に向けたスピン検出効率の極大化
    日本学術振興会:
    Date (from‐to) : 2011 -2012

Teaching Experience

  • Physics scientific experimentPhysics scientific experiment Fukuoka University
  • Basic seminarBasic seminar Fukuoka University
  • Physics experimentPhysics experiment Fukuoka University

Social Contribution

  • リフレッシュ理科教室
    Date (from-to) : 2016
    Role : Others
    Sponser, Organizer, Publisher  : 応用物理学会九州支部

Academic Contribution

  • 2018年応用物理学会九州支部学術講演会実行委員
    Date (from-to) :2018/10/11-2018/12/09
    Role: Planning etc
    Type: Academic society etc
    Organizer, responsible person: 応用物理学会九州支部・西田昭彦
  • 日本磁気学会第41回学術講演会現地実行委員
    Date (from-to) :2017/03/09-2017/09/20
    Role: Planning etc
    Type: Academic society etc
    Organizer, responsible person: 日本磁気学会・松山公秀


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