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Explore New Materials and Physics
for Future Spintronics
Welcome to the website of the Ohya Research Group in The University of Tokyo. We are trying to explore new materials and physics for future spintronics by developing various single-crystalline thin films, heterostructures, and magnetic nano structures.
Research Interests
- Ferromagnetic semiconductors
- Ferromagnetic particles in semiconductors
- Ferromagnetic quantum heterostructures
- Spin-dependent transport
- Magnetooptical properties
- Coulomb blockade in ferromagnetic nano-particles in semiconductors
- Oxide heterostructures
Research facilities
Molecular beam epitaxy (Epiquest Inc.)
We are mainly managing two MBE systems, in which we are growing different material systems.
300mK He-free cryostat (Janis Research Inc.)
Pump and probe measurement system
(We are developing the pump&probe system in collaboration with the Prof. Ohtsu and Prof. Yatsui Lab.)
Other facilities
We can use the facilities of Tanaka lab in the Dept. of Electrical Engineering and Information Systems. Also, we can use the Taketa clean room (class 1-1000) and the facilities of the Advanced Characterization Nanotechnology Platform (SEM, STEM, SQUID, PPMS, XRD etc).
Members
Associate Professor | Shinobu Ohya | ohya[at]cryst.t.u-tokyo.ac.jp |
Research Associate | Le Duc Anh | anh[at]cryst.t.u-tokyo.ac.jp |
D3 | Ryota Suzuki | suzuki_ryota[at]cryst.t.u-tokyo.ac.jp |
M2 | Shingo Kaneta | skaneta[at]cryst.t.u-tokyo.ac.jp |
M2 | Yuriko Tadano | tadano[at]cryst.t.u-tokyo.ac.jp |
M1 | Chenhao Xia | xia[at]cryst.t.u-tokyo.ac.jp |
Secretary | Rie Nakatsuji | nakatsuji[at]cryst.t.u-tokyo.ac.jp |
Contact
Shinobu Ohya (Ph. D)
Associate Professor
Department of Electrical Engineering and Information Systems,
The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Tel: +81-3-5841-6773
Fax: +81-3-5841-0525
Email: ohya@cryst.t.u-tokyo.ac.jp
EDUCATION
- Ph. D., Electronic Engineering, 2005, The University of Tokyo, Japan
- MS., Electronic Engineering, 2002, The University of Tokyo, Japan
- BS., Electronic Engineering, 2000, The University of Tokyo, Japan
CAREER HISTORY
- Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellow for Research Abroad
2011 February to 2013 February
University of California Santa Barbara, USA
(Prof. C. J. Palmstrøm Lab., Prof. John M. Martinis Lab) - Associate Professor
2010 April to present
Department of Electrical Engineering and Information Systems,
The University of Tokyo, Japan - Researcher of Japan Science and Technology Agency (JST) PRESTO
2006 October - 2010 March
- Research Associate, 2006 April -2010 March
Department of Electrical Engineering and Information Systems,
The University of Tokyo, Japan - Research Associate 2005 April -2006 March
Department of Electronic Engineering,
The University of Tokyo, Japan
Access
Engineering Building 10 room 430 in The University of Tokyo
Address: 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
TEL: +81-3-5841-6773, FAX: +81-3-5841-0525
- 5 mins walk from the Nezu Station (C14) of on the Tokyo-Metro Chiyoda Line.
- 10 mins walk from the Todaimae Station (N11) on the Tokyo-Metro Namboku Line.
- 25 mins walk from the Hongo-sanchome Station (M21, E08) on the Tokyo-Metro Marunouchi Line or the Toei Oedo Line.
Publications
- S. Kaneta-Takada, Y. K. Wakabayashi, Y. Krockenberger, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto, Critical thickness for observing quantum transport of Weyl fermions in ultra-high quality SrRuO3 films, Appl. Phys. Lett. 118, 92408 (2021).
- Y. K. Wakabayashi, S. Kaneta-Takada, Y. Krockenberger, K. Takiguchi, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto, Stoichiometry effects on the magnetotransport in epitaxial SrRuO3 films, AIP Advances 11, 035226 (2021).
- Y. Takeda, M. Kobayashi, Y. Saitoh, H. Yamagami, A. Fujimori, S. Ohya, P. N. Hai, and M. Tanaka, Direct observation of the magnetic ordering process in the ferromagnetic semiconductor Ga1-xMnxAs via soft X-ray magnetic circular dichroism, J. Appl. Phys. 128, 213902 (2020). Selected as Featured Article.
- M. Jiang, H. Asahara, S. Sato, S. Ohya, and M. Tanaka, Suppression of the field-like torque for efficient magnetization switching in a spin–orbit ferromagnet, Nature Electronics (2020), published online.
Press release "Lower current leads to highly efficient memory" - Y. Du, S. Arai, S. Kaneta-Takada, L. D. Anh, S. Karube, M. Kohda, S. Ohya, and J. Nitta, Room-temperature perpendicular magnetic anisotropy of Pt/Co/AlOx trilayers on SrTiO3 (001), AIP Advances 10, 105010 (2020).
- S. Kaneta, M. Yamada, S. Sato, S. Arai, L. D. Anh, K. Hamaya, and S. Ohya, Enhancement of the spin Hall angle by the interdiffusion of atoms in Co2FeAl0.5Si0.5/n-Ge heterostructures, Phys. Rev. Applied 14, 024096 (2020).
- R. Suzuki, Y. Tadano, M. Tanaka, and S. Ohya, Large tunnel magnetoresistance in a fully epitaxial double-barrier magnetic tunnel junction of Fe/MgO/Fe/γAl2O3/Nb-doped SrTiO3, AIP Adv. 10, 085115 (2020).
- L. D. Anh, S. Kaneta, M. Tokunaga, M. Seki, H. Tabata, M. Tanaka, and S. Ohya, High-mobility two-dimensional hole gas at a SrTiO3 interface, Adv. Mater. 32, 1906003 (2020).
- S. Goel, L. D. Anh, S. Ohya, and M. Tanaka, Temperature dependence of magnetic anisotropy in heavily Fe-doped ferromagnetic semiconductor (Ga,Fe)Sb, J. Appl. Phys. 127, 023904 (2020).
- S. Ohya, D. Araki, L. D. Anh, S. Kaneta, M. Seki, H. Tabata, and M. Tanaka, Efficient intrinsic spin-to-charge current conversion in an all-epitaxial single-crystal perovskite-oxide heterostructure of La0.67Sr0.33MnO3/LaAlO3/SrTiO3, Phys. Rev. Res. 2, 012014 (R) (2020).
- L. D. Anh, T. Yamashita, H. Yamasaki, D. Araki, M. Seki, H. Tabata, M. Tanaka, and S. Ohya, Ultralow-power orbital-controlled magnetisation rotation using a ferromagnetic oxide interface, Phys. Rev. Applied (Letter) 12, 041001 (2019).
- S. Goel, L. D. Anh, S. Ohya, and M. Tanaka, In-plane to perpendicular magnetic anisotropy switching in heavily-Fe-doped ferromagnetic semiconductor (Ga,Fe)Sb with high Curie temperature, Phys. Rev. Mater. 3, 084417 (2019).
- M. Jiang, H. Asahara, S. Sato, T. Kanaki, H. Yamasaki, S. Ohya and M. Tanaka, Efficient full spin-orbit torque switching in a single layer of a perpendicularly magnetized single-crystalline ferromagnet, Nat. Commun. 10, 2590 (2019).
Press Release → Small currents for big gains in spintronics - T. Nakamura, L. D. Anh, Y. Hashimoto, S. Ohya, M. Tanaka, and S. Katsumoto, Evidence for Spin-Triplet Electron Pairing in the Proximity-Induced Superconducting State of an Fe-Doped InAs Semiconductor, Phys. Rev. Lett. 122, 107001 (2019).
- T. Ishii, H. Yamakawa, T. Kanaki, T. Miyamoto, N. Kida, H. Okamoto, M. Tanaka, and S. Ohya, Large terahertz magnetization response observed in ferromagnetic nanoparticles, Appl. Phys. Lett. 114, 062402 (2019).Selected as Featured Article.
UTokyo Focus: Nanoparticles help realize ‘spintronic’ devices - T. Kanaki, S. Matsumoto, S. K. Narayananellore, H. Saito, Y. Iwasa, M. Tanaka, and S. Ohya, Room-temperature side-gate-induced current modulation in a magnetic tunnel junction with an oxide-semiconductor barrier for vertical spin-MOSFET operation, Appl. Phys. Express 12, 23009 (2019).
- S. Goel, L. D. Anh, S. Ohya, and M. Tanaka, Ferromagnetic resonance and control of magnetic anisotropy by epitaxial strain in ferromagnetic semiconductor (Ga0.8,Fe0.2)Sb at room temperature, Phys. Rev. B 99, 014431 (2019).
- T. Kanaki, H. Yamasaki, H. Terada, Y. Iwasa, S. Ohya, and M. Tanaka, Improved performance of a GaMnAs-based vertical spin electric double-layer transistor, Jpn. J. Appl. Phys. (Rapid Commun.) 57, 090301 (2018).
- T. Kanaki, H. Yamasaki, T. Koyama, D. Chiba, S. Ohya, M. Tanaka, Large current modulation and tunneling magnetoresistance change by a side-gate electric field in a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor, Sci. Rep. 8, 7195 (2018).
- T. Ishii, H. Yamakawa, T. Kanaki, T. Miyamoto, N. Kida, H. Okamoto, M. Tanaka, and S. Ohya, Ultrafast magnetization modulation induced by the electric field component of a terahertz pulse in a ferromagnetic-semiconductor thin film, Sci. Rep. 8, 6901 (2018).
- T. Nakamura, L. D. Anh, Y. Hashimoto, Y. Iwasaki, S. Ohya, M. Tanaka, and S. Katsumoto, Proximity-Induced Superconductivity in a Ferromagnetic Semiconductor (In,Fe)As, Journal of Physics: Conference Series 969, 012036 (2018).
- R. Suzuki, Y. K. Wakabayashi, K. Okamoto, M. Tanaka, and S. Ohya, Quantum size effect in an Fe quantum well detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode, Appl. Phys. Lett. 112, 152402 (2018).
- H. Terada, S. Ohya, and M. Tanaka, Intrinsic transmission magnetic circular dichroism spectra of GaMnAs, AIP Advances 8, 035009 (2018).
- H. Asahara, T. Kanaki, S. Ohya, and M. Tanaka, Large spin-valve effect in a lateral spin-valve device based on ferromagnetic semiconductor GaMnAs, Appl. Phys. Express 11, 033003 (2018).
- K. Takiguchi, Y. K. Wakabayashi, K. Okamoto, M. Tanaka, and S. Ohya, Fe concentration dependence of tunneling magnetoresistance in magnetic tunnel junctions using group-IV ferromagnetic semiconductor GeFe, AIP Advances 7, 105202 (2017).
- S. Ohya, A. Yamamoto, T. Yamaguchi, R. Ishikawa, R. Akiyama, L. D. Anh, S. Goel, Y. K. Wakabayashi, S. Kuroda, and M. Tanaka, Observation of the inverse spin Hall effect in the topological crystalline insulator SnTe using spin pumping, Phys. Rev. B 96, 094424 (2017).
- L. D. Anh, N. Okamoto, M. Seki, H. Tabata, M. Tanaka, and S. Ohya, Hidden peculiar magnetic anisotropy at the interface in a ferromagnetic perovskite-oxide heterostructure, Sci. Rep. 7, 8715 (2017).
- H. Terada, S. Ohya, L. D. Anh, Y. Iwasa, and M. Tanaka, Magnetic anisotropy control by applying an electric field to the side surface of ferromagnetic films, Sci. Rep. 7, 5618 (2017).
- T. Matou, K. Takeshima, L. D. Anh, M. Seki, H. Tabata, M. Tanaka, and S. Ohya, Reduction of the dead layer and observation of tunneling magnetoresistance in La0.67Sr0.33MnO3-based heterostructures with a LaMnO3 layer, Appl. Phys. Lett. 110, 212406 (2017).
- I. Muneta, T. Kanaki, S. Ohya, and M. Tanaka, Artificial control of the bias-voltage dependence of tunnelling anisotropic magnetoresistance using quantization in a single-crystal ferromagnet, Nature Commun. 8, 15387 (2017).<UTokyo Research News>.
- S. Sakamoto, Y. K. Wakabayashi, Y. Takeda, S.-i. Fujimori, H. Suzuki, Y. Ban, H. Yamagami, M. Tanaka, S. Ohya, and A. Fujimori, Origin of robust nanoscale ferromagnetism in Fe-doped Ge revealed by angle-resolved photoemission spectroscopy and rst-principles calculation, Phys. Rev. B 95, 075203 (2017).
- Y. K. Wakabayashi, R. Akiyama, Y. Takeda, M. Horio, G. Shibata, S. Sakamoto, Y. Ban, Y. Saitoh, H. Yamagami, A. Fujimori M. Tanaka, and S. Ohya, Origin of the large positive magnetoresistance of Ge1-xMnx granular thin films, Phys. Rev. B 95, 14417 (2017).
- Y. K. Wakabayashi, K. Okamoto, Y. Ban, S. Sato, M. Tanaka, and S. Ohya, Tunneling magnetoresistance in trilayer structures composed of group-IV ferromagnetic semiconductor GeFe, MgO, and Fe, Appl. Phys. Express 9, 123001 (2016). Selected as Spotlights.
- T. Kanaki, T. Koyama, D. Chiba, S. Ohya, and M. Tanaka, Spin-dependent transport and current modulation in a current-in-plane spin-valve field-effect transistor, Appl. Phys. Lett. 109, 152403 (2016).
- I. Muneta, S. Ohya, H. Terada and M. Tanaka, Sudden restoration of the band ordering associated with the ferromagnetic phase transition in a semiconductor, Nature Commun.7, 12013 (2016). <UTokyo Research News>.
- T. Ishii, T. Kawazoe, Y. Hashimoto, H. Terada, I. Muneta, M. Ohtsu, M. Tanaka, and S. Ohya, Electronic structure near the Fermi level in the ferromagnetic semiconductor GaMnAs studied by ultrafast time-resolved light-induced reflectivity measurements, Phys. Rev. B 93, 241303(R) (2016).
- Y. K. Wakabayashi, S. Sakamoto, Y. Takeda, K. Ishigami, Y. Takahashi, Y. Saitoh, H. Yamagami, A. Fujimori, M. Tanaka, and S. Ohya, Room-temperature local ferromagnetism and its nanoscale expansion in the ferromagnetic semiconductor Ge1-xFex, Sci. Rep. 6, 23295 (2016).
- T. Kanaki, H. Asahara, S. Ohya, and M. Tanaka, Spin-dependent transport properties of a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor structure, Appl. Phys. Lett. 107, 242401 (2015).
- H. Terada, S. Ohya, and M. Tanaka, Intrinsic magneto-optical spectra of GaMnAs, Appl. Phys. Lett. 106, 222406 (2015).
- Y. K. Wakabayashi, Y. Ban, S. Ohya, and M. Tanaka, Annealing-induced enhancement of ferromagnetism and nano-particle formation in ferromagnetic-semiconductor GeFe, Phys. Rev. B 90, 205209 (2014).
- Y. K. Wakabayashi, S. Ohya, Y. Ban, and M. Tanaka, Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe, J. Appl. Phys. 116, 173906 (2014).
- M. Kobayashi, I. Muneta, Y. Takeda, Y. Harada, A. Fujimori, J. Krempasky, T. Schmitt, S. Ohya, M. Tanaka, M. Oshima, and V. N. Strocov, "Unveiling the impurity band inducing ferromagnetism in magnetic semiconductor (Ga,Mn)As", Phys. Rev. B 89, 205204 (2014).
- M. Kobayashi, H. Niwa, Y. Takeda, A. Fujimori, Y. Senba, H. Ohashi, A. Tanaka, S. Ohya, P. N. Hai, M. Tanaka, Y. Harada, and M. Oshima, "Electronic Excitations of a Magnetic Impurity State in the Diluted Magnetic Semiconductor (Ga,Mn)As", Phys. Rev. Lett. 112, 107203 (2014). Press Release
- S. Ohya, B. Chiaro, A. Megrant, C. Neill, R. Barends, Y. Chen, J. Kelly, D. Low, J. Mutus, P. J. J. O’Malley, P. Roushan, D. Sank, A. Vainsencher, J. Wenner, T. C. White, Y. Yin, B. D. Schultz, C. J. Palmstrøm, B. A. Mazin, A. N. Cleland, and John M. Martinis, “Room temperature deposition of sputtered TiN films for superconducting coplanar waveguide resonators”, Supercond. Sci. Technol. 27, 015009 (2014).
- M. Tanaka, S. Ohya, and P. N. Hai, (invited review) “Recent Progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport”, Appl. Phys. Rev. 1, 011102 (2014).
- I. Muneta, H. Terada, S. Ohya, and M. Tanaka, “Anomalous Fermi level behavior in GaMnAs at the onset of ferromagnetism”, Appl. Phys. Lett. 103, 032411 (2013).
- L. Feigl, B. D. Schultz, S. Ohya, D. G. Ouellette, A. Kozhanov, and C. J. Palmstrøm, “Structural and transport properties of epitaxial PrNiO3 thin filmsgrown by molecular beam epitaxy”, J. Cryst. Growth 366, 51 (2013).
- M. Kobayashi, I. Muneta, T. Schmitt, L. Patthey, S. Ohya, M. Tanaka, M. Oshima, V. N. Strocov, “Digging up bulk band dispersion buried under a passivation layer”, Appl. Phys. Lett. 101, 242103 (2012).
- S. Ohya, I. Muneta, Y. Xin, K. Takata, and M. Tanaka, “Valence-band structure of ferromagnetic semiconductor (InGaMn)As”, Phys. Rev. B 86, 094418 (2012).
- I. Muneta, S. Ohya, and M. Tanaka, “Spin-dependent tunneling transport in a ferromagnetic GaMnAs and un-doped GaAs double-quantum-well heterostructure”, Appl. Phys. Lett. 100, 162409 (2012).
- R. Akiyama, S. Ohya, P. N. Hai, and M. Tanaka, “Magnetoresistance enhanced by inelastic cotunneling in a ferromagnetic MnAs nanoparticle sandwiched by nonmagnetic electrodes”, J. Appl. Phys. 111, 063716 (2012).
- S. Ohya, K. Takata, and M. Tanaka, "Nearly non-magnetic valence band of the ferromagnetic semiconductor GaMnAs", Nature Phys. 7, 342-347 (2011).
- S. Yada, R. Okazaki, S. Ohya, and M. Tanaka, "Single-crystalline ferromagnetic alloy semiconductor Ge1-xMnx grown on Ge", Appl. Phys. Express 3, 123002 (2010). Selected as the Editors' Choice from APEX and JJAP.
- P. N. Hai, S. Ohya, and M. Tanaka, "Long spin-relaxation time in a single metal nanoparticle", Nature Nanotech. 5, 593 - 596 (2010).
- S. Ohya, I. Muneta, P. N. Hai, and M. Tanaka, "Valence-Band Structure of the Ferromagnetic-Semiconductor GaMnAs Studied by Spin-Dependent Resonant Tunneling Spectroscopy", Phys. Rev. Lett. 104, 167204 (2010).
- S. Ohya, I. Muneta, and M. Tanaka, "Quantum-level control in a III-V-based ferromagnetic-semiconductor heterostructure with a GaMnAs quantum well and double barriers", Appl. Phys. Lett. 96, 052505 (2010).
- S. Ohya, I. Muneta, P. N. Hai, and M. Tanaka, "GaMnAs-based magnetic tunnel junctions with an AlMnAs barrier", Appl. Phys. Lett. 95, 242503 (2009).
- P. N. Hai, S. Ohya, M. Tanaka, S. E. Barnes, and S. Maekawa, "Electromotive force and huge magnetoresistance in magnetic tunnel junctions", Nature 458, 489-493 (2009).
- M. Yokoyama, S. Ohya, and M. Tanaka, "In-Plane Uniaxial Magnetic Anisotropy of [(InyGa1-y)1-xMnx]As Characterized by Planar Hall Effect", Jpn. J. Appl. Phys. 48, 023001 (2009).
- A. M. Nazmul, H. T. Lin, S. Ohya, and M. Tanaka, "Planar Hall Effect and Magnetic Anisotropy in a Mn delta-doped GaAs/p-AlGaAs Heterostructure", IEEJ Transactions on Electrical and Electronic Engineering 3, pp.394-398 (2008).
- P. N. Hai, Y. Sakata, M. Yokoyama, S. Ohya, and M. Tanaka, "Spin valve effect by ballistic transport in ferromagnetic metal (MnAs) / semiconductor (GaAs) hybrid heterostructures", Phys. Rev. B 77, 214435 (2008).
- M. Yokoyama, S. Ohya, and M. Tanaka,, "Magnetic anisotropy of ferromagnetic semiconductor [(InGa)Mn]As thin films", phys. stat. sol. (c) 5, 2901 (2008).
- Y. Takeda, M. Kobayashi, T. Okane, T. Ohkochi, J. Okamoto, Y. Saito, K. Kobayashi, H. Yamagami, A. Fujimori, A. Tanaka, J. Okabayashi, M. Oshima, S. Ohya, P. N. Hai, and M. Tanaka, "Nature of Magnetic Coupling between Mn Ions in As-Grown Ga1-xMnxAs Studied by X-ray Magnetic Circular Dichroism", Phys. Rev. Lett. 100, 247202 (2008).
- A. M. Nazmul, H. T. Lin, S. N. Tran, S. Ohya, and M. Tanaka, "Planar Hall effect and uniaxial in-plane magnetic anisotropy in Mn -doped GaAs/p-AlGaAs heterostructures", Phys. Rev. B 77, 155203 (2008).
- K. Ohno, S. Ohya, and M. Tanaka, "Properties of Heavily Mn-doped GaMnAs with Curie Temperature of 172.5 K", J. Supercond. Nov. Magn. 20, 417-420 (2007).
- S. Ohya, P. N. Hai, Y. Mizuno, and M. Tanaka, "Quantum-size effect and tunneling magnetoresistance in ferromagnetic-semiconductor quantum heterostructures", Phys. Rev. B 75, 155328 (2007).
- Y. Mizuno, S. Ohya, P. N. Hai, and M. Tanaka, "Spin-dependent transport properties in GaMnAs-based spin hot-carrier transistors", Appl. Phys. Lett. 90, 162505 (2007).
- S. Ohya, K. Ohno, and M. Tanaka, "Magneto-optical and magnetotransport properties of heavily Mn-doped GaMnAs", Appl. Phys. Lett. 90, 112503 (2007).
- M. Yokoyama, S. Ohya, and M. Tanaka, "Fabrication, structural and magnetic properties of InAlMnAs and InAlAs:MnAs granular thin films", J. Cryst. Growth. 301-302, 627-630 (2007).
- M. Yokoyama, S. Ohya, and M. Tanaka, "Molecular beam epitaxy growth, magnetic and structural properties of MnAs thin films grown on InP(001) and InGaAsP", J. Cryst. Growth. 301-302, 615-617 (2007).
- P. N. Hai, K. Takahashi, M. Yokoyama, S. Ohya, and M. Tanaka, "Magnetic properties of MnAs nanoclusters embedded in a GaAs semiconductor matrix", J. Magn. Magn. Mater. 310, 1932-1934 (2007).
- P. N. Hai, M. Yokoyama, S. Ohya, and M. Tanaka, "Tunneling magnetoresistance of MnAs thin film / GaAs / AlAs / GaAs:MnAs nanoclusters and its AlAs barrier thickness dependence", Appl. Phys. Lett. 89, 242106 (2006).
- S. Ohya, P. N. Hai, Y. Mizuno, and M. Tanaka, "Resonant tunneling effect and tunneling magnetoresistance in GaMnAs quantum-well double-barrier heterostructures", phys. stat. sol. (c) 3 4184-4187 (2006).
- M. Yokoyama, S. Ohya, and M. Tanaka, "Growth and magnetic properties of epitaxial MnAs thin films grown on InP (001)", Appl. Phys. Lett. 88, 012504 (2006).
- P. N. Hai, M. Yokoyama, S. Ohya, and M. Tanaka, "Spin polarized tunneling in III-V based heterostructures with a ferromagnetic MnAs thin film and GaAs:MnAs nanoclusters", Physica E 32, 416-418 (2006).
- A. Fujimori, J. Okabayashi, Y. Takeda, T. Mizokawa, J. Okamoto, K. Mamiya, Y. Saitoh, Y. Muramatsu, M. Oshima, S. Ohya, and M. Tanaka, "Photoemission and core-level magnetic circular dichroism studies of diluted magnetic semiconductors", Journal of Electron Spectroscopy and Related Phenomena 144-147, 701-5 (2005).
- S. Ohya, P. N. Hai, and M Tanaka, "Tunneling magnetoresistance in GaMnAs / AlAs / InGaAs / AlAs / GaMnAs double-barrier magnetic tunnel junctions", Appl. Phys. Lett. 87, 012105 (2005).
- S. Ohya, H. Kobayashi, and M. Tanaka, "Magneto-optical properties and Curie temperature (~130 K) of heavily Mn-doped quaternary alloy ferromagnetic semiconductor (InGaMn)As grown on InP", Physica E 21, 975 (2004).
- S. Ohya, H. Kobayashi, and M. Tanaka, "Magnetic Properties of Heavily Mn-doped Quaternary Alloy Ferromagnetic Semiconductor (InGaMn)As Grown on InP", Appl. Phys. Lett. 83, 2175-2177 (2003); ibid 83, 4450(2003).
- S. Ohya, H. Yamaguchi, and M. Tanaka, "Properties of Quaternary Alloy Magnetic Semiconductor (InGaMn)As Grown on InP", J. Superconductivity 16, 139-142 (2003).
- S. Ohya, Y. Higo, H. Shimizu, J. M. Sun and M. Tanaka," Growth and Properties of Quaternary Alloy Magnetic Semiconductor (InGaMn)As", Jpn. J. Appl. Phys. 41, L24 - L27 (2002).