独立行政法人理化学研究所 基幹研究所 物質機能創成研究領域 交差相関物性科学研究グループ

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Members (CMRG)

徳永祐介

氏名

徳永 祐介

研究分野

物性物理学

略歴

1977年 東京都生まれ
1996年3月 鹿児島県立鶴丸高等学校 卒業
2000年3月 東京大学工学部物理工学科 卒業
2005年3月 東京大学大学院工学系研究科物理工学専攻 博士課程修了 博士(工学)
2005年4月 - 2007年3月 科学技術振興機構 ERATO十倉スピン超構造プロジェクト 研究員
2007年4月 - 2011年3月 科学技術振興機構 ERATO十倉マルチフェロイックスプロジェクト マルチフェロイックス創製グループ 研究員
2008年4月 - 2011年3月 理化学研究所 基幹研究所 物質機能創成研究領域
交差相関物性科学研究グループ 交差相関物質研究チーム 客員研究員
2011年4月 理化学研究所 基幹研究所 物質機能創成研究領域
交差相関物性科学研究グループ 交差相関物質研究チーム 基幹研究所研究員

学会活動・社会貢献

日本物理学会会員、アメリカ物理学会会員

研究業績内容

ペロブスカイト型マンガン酸化物をはじめとする強相関電子系、マルチフェロイック物質等における交差相関物性を研究の対象としてきた。主な研究業績は、

主な論文・業績

[原著論文]
  1. S. Ishiwata, Y. Tokunaga, Y. Taguchi, and Y. Tokura,
    "High-Pressure Hydrothermal Crystal Growth and Multiferroic Properties of a Perovskite YMnO3"
    J. Am. Chem. Soc. 133, 13818 (2011).
  2. Y. Tokunaga, D. Okuyama, T. Kurumaji, T. Arima, H. Nakao, Y. Murakami, Y. Taguchi, and Y. Tokura,
    "Multiferroicity in NiBr2 with long-wavelength cycloidal spin structure on a triangular lattice"
    Phys. Rev. B 84, 060406(R) (2011).
  3. S. Ishiwata, M. Tokunaga, Y. Kaneko, D. Okuyama, Y. Tokunaga, S. Wakimoto, K. Kakurai, T. Arima, Y. Taguchi, and Y. Tokura,
    "Versatile helimagnetic phases under magnetic fields in cubic perovskite SrFeO3"
    Phys. Rev. B. 84, 054427 (2011).
  4. R. Iida, T. Satoh, T. Shimura, K. Kuroda, B. A. Ivanov, Y. Tokunaga, and Y. Tokura,
    "Spectral dependence of photoinduced spin precession in DyFeO3"
    Phys. Rev. B 84, 064402 (2011).
  5. T. Kurumaji, S. Seki, S. Ishiwata, H. Murakawa, Y. Tokunaga, Y. Kaneko, and Y. Tokura,
    "Magnetic-Field Induced Competition of Two Multiferroic Orders in a Triangular-Lattice Helimagnet MnI2"
    Phys. Rev. Lett. 106, 167206 (2011).
  6. B. Bryant, Ch. Renner, Y. Tokunaga, Y. Tokura, and G. Aeppli,
    "Imaging oxygen defects and their motion at a manganite surface"
    Nat. Commun. 2, 202 (2011).
  7. M. Nakamura, Y. Tokunaga, M. Kawasaki, and Y. Tokura,
    "Multiferroicity in an orthorhombic YMnO3 single-crystal film"
    Appl. Phys. Lett. 98, 082902 (2011).
  8. Y. Tokunaga, Y. Kaneko, D. Okuyama, S. Ishiwata, T. Arima, S. Wakimoto, K. Kakurai, Y. Taguchi, and Y. Tokura,
    "Multiferroic M-type hexaferrites with a room-temperature conical state and magnetically controllable spin helicity"
    Phys. Rev. Lett. 105, 257201 (2010).
  9. I. Ishii, Y. Tokunaga, J. Fujioka, Y. Onose, and Y. Tokura,
    "Optical characterization of spin-charge-orbital orders in Pr(Sr1-yCay)2Mn2O7"
    Phys. Rev. B 82, 245103 (2010).
  10. S. Seki, T. Kurumaji, S. Ishiwata, H. Matsui, H. Murakawa, Y. Tokunaga, Y. Kaneko, T. Hasegawa, and Y. Tokura,
    "Cupric chloride CuCl2 as an S = 1/2 chain multiferroic"
    Phys. Rev. B 82, 064424 (2010).
  11. R. Mathieu, M. Hudl, P. Nordblad, Y. Tokunaga, Y. Kaneko, Y. Tokura, H. Aruga Katori, and A. Ito,
    "Isothermal remanent magnetization and the spin dimensionality of spin glasses"
    Phil. Mag. Lett. 90, 723 (2010).
  12. S. Ishiwata, Y. Kaneko, Y. Tokunaga, Y. Taguchi, T. Arima, and Y. Tokura,
    "Perovskite manganites hosting versatile multiferroic phases with symmetric and antisymmetric exchange strictions"
    Phys. Rev. B 81, 100411 (2010).
  13. S. Horiuchi, Y. Tokunaga, G. Giovannetti, S. Picozzi, H. Itoh, R. Shimano, R. Kumai, and Y. Tokura,
    "Above-room-temperature ferroelectricity in a single-component molecular crystal"
    Nature 463, 789 (2010).
  14. H. Itoh, Y. Tokunaga, N. Kida, R. Shimano, and Y. Tokura,
    "Charge-ordering-induced polar domains and domain walls in a bilayered manganite Pr(Sr0.15Ca0.85)2Mn2O7"
    Appl. Phys. Lett. 96, 032902 (2010).
  15. D. Okuyama, Y. Tokunaga, R. Kumai, Y. Taguchi, T. Arima, and Y. Tokura,
    "Lattice-form-dependent orbital shape and charge disproportionation in charge- and orbital-ordered manganites"
    Phys. Rev. B 80, 064402 (2009).
  16. Y. Tokunaga, N. Furukawa, H. Sakai, Y. Taguchi, T. Arima, and Y. Tokura,
    "Composite domain walls in a multiferroic perovskite ferrite"
    Nature Materials 8, 558 - 562 (2009).
  17. S. Ishiwata, Y. Taguchi, Y. Tokunaga, H. Murakawa, Y. Onose, and Y. Tokura,
    "Electric polarization induced by transverse magnetic field in the anisotropy-controlled conical helimagnet Ba2(Mg1-xZnx)2Fe12O22"
    Phys. Rev. B 79, 180408(R) (2009).
  18. Y. Tokunaga, R. Kumai, N. Takeshita, Y. Kaneko, J. P. He, T. Arima, and Y. Tokura,
    "Effects of uniaxial stress on orbital stripe direction in half doped layered manganites: Eu0.5Ca1.5MnO4 and Pr(Sr, Ca)2Mn2O7"
    Phys. Rev. B 78, 155105 (2008).
  19. Y. Tokunaga, S. Iguchi, T. Arima, and Y. Tokura,
    "Magnetic-Field-Induced Ferroelectric State in DyFeO3"
    Phys. Rev. Lett. 101, 097205 (2008).
  20. S. Horiuchi, R. Kumai, Y. Tokunaga, and Y. Tokura,
    "Proton Dynamics and Room-Temperature Ferroelectricity in Anilate Salts with a Proton Sponge"
    J. Am. Chem. Soc. 130, 13382 (2008).
  21. Y. Tokunaga, T. J. Sato, M. Uchida, R. Kumai, Y. Matsui, T. Arima, and Y. Tokura,
    "Versatile and competing spin-charge-orbital orders in the bilayered manganite system Pr(Sr1-yCay)2Mn2O7"
    Phys. Rev. B 77, 064428 (2008).
  22. Y. S. Lee, Y. Tokunaga, T. Arima, and Y. Tokura,
    "Change in optical anisotropy with rotation of orbital stripe in a half-doped bilayer manganite"
    Phys. Rev. B 75, 174406 (2007).
  23. Y. Tokunaga, Th. Lottermoser, Y. S. Lee, R. Kumai, M. Uchida, T. Arima, and Y. Tokura,
    "Rotation of orbital stripes and the consequent charge-polarized state in bilayer manganites"
    Nature Mater. 5, 937 (2006).
  24. Y. S. Lee, T. Arima, S. Onoda, Y. Okimoto, Y. Tokunaga, R. Mathieu, X. Z. Yu, J. P. He, Y. Kaneko, Y. Matsui, N. Nagaosa, and Y. Tokura,
    "Correlation of electronic structure and ordered charge and orbital patterns for single-layered manganites in a wide hole-doping range (0<x<1)"
    Phys. Rev. B 75, 144407 (2007).
  25. H. Song, M. Tokunaga, Y. Tokunaga, S. Imamori, and T. Tamegai,
    "Multivalued memory effects in electronic phase-change manganites"
    Phys. Rev. B 74, 052404 (2006).
  26. Y. Tokunaga, A. Kaneko, J. P. He and T. Arima, A. Sawa, T. Fujii, M. Kawasaki, and Y. Tokura,
    "Colossal electroresistance effect at metal electrode/La1-xSr1+xMnO4 interfaces"
    Appl. Phys. Lett. 88, 223507 (2006).
  27. Y. S. Lee, S. Onoda, T. Arima, Y. Tokunaga, J. P. He, Y. Kaneko, N. Nagaosa, and Y. Tokura,
    "In-plane anisotropy of the electronic structure for the charge- and orbital-ordered state in half-doped manganite with layered structure"
    Phys. Rev. Lett. 97, 077203 (2006).
  28. Y. Tokunaga, M. Tokunaga, and T. Tamegai,
    "Magnetic domain structures and anisotropic in-plane transport in layered manganites"
    Phys. Rev. B 71, 012408 (2005).
  29. M. Tokunaga, H. Song, Y. Tokunaga, and T. Tamegai,
    "Current oscillation and low-field colossal magnetoresistance effect in phase-separated manganites"
    Phys. Rev. Lett. 94, 157203 (2005).
  30. S. Kasahara, Y. Tokunaga, N. Kameda, M. Tokunaga, and T. Tamegai,
    "Local magnetization anomalies and inhomogeneous vortex penetration in the crossing-lattices state of Bi2Sr2CaCu2O8+y"
    Phys. Rev. B 71, 224505 (2005).
  31. M. Tokunaga, Y. Tokunaga, and T. Tamegai,
    "Imaging of percolative conduction paths and their breakdown in phase separated (La1-yPry)0.7Ca0.3MnO3 with y=0.7"
    Phys. Rev. Lett. 93, 037203 (2004).
  32. M. Tokunaga, M. Kobayashi, Y. Tokunaga, and T. Tamegai,
    "Visualization of vortex chains in Bi2Sr2CaCu2O8+y by magneto-optical imaging"
    Phys. Rev. B 66, 060507(R) (2002).
[招待講演]
  1. Y. Tokunaga, N. Furukawa, H. Sakai, S. Iguchi, Y. Taguchi, T. Arima, and Y. Tokura,
    "Multiferroicity in Rare-Earth Orthoferrite Systems"
    Moscow International Symposium on Magnetism, August 21-25, 2011, Moscow.
  2. Y. Tokunaga,
    "Ferroelectricity with Ferromagnetic Moment in Orthoferrites"
    Annual APS March Meeting 2010, March 15-19, 2010, Portland, OR.
  3. Y. Tokunaga, Th. Lottermoser, Y. S. Lee, R. Kumai, T. J. Sato, M. Uchida, T. Arima, and Y. Tokura,
    "Spontaneous rotation of orbital stripes and ferroelectric state in bilayer manganites"
    Workshop on Competing Interactions and Colossal Responses in Transition Metal Compounds, July 16-22, 2006, telluride, CO.