今後の開催予定

神戸計算科学研究機構において、物性物理関連のセミナーを開催しています。計算物性物理に限らず、実験、計算機科学分野など幅広いトピックを取り上げています。参加は自由です。皆さま奮ってご参加ください。

世話人:坂井 徹 (SPRING-8)、中野博生 (兵庫県立大)、大塚雄一(理研AICS)、藤堂眞治 (東大理)
メールでの案内をご希望の方は、藤堂 wistaria@phys.s.u-tokyo.ac.jp までご連絡ください。

また、CMSI神戸拠点(AICS R501)にお立ち寄りの方は、前日までに「CMSI拠点訪問 / 利用連絡フォーム」からご連絡をお願いします。

第16回セミナー
  • 日時 Date: 2015年11月20日(金) Nov. 20 (Fri), 2015 16:30-17:30
  • 場所 Place: 理化学研究所 計算科学研究機構 (1Fセミナー室(1階展示ホール横), 1F Seminar Room, RIKEN AICS
    • ゲストカード(入構証)は必要ありません。玄関から直接セミナー室にお進みください
  • 講師 Lecturer: Timothy Ziman (Institut Laue-Langevin, LPMMC, University Joseph-Fourier, CNRS, Grenoble)
  • タイトル Title: Non-linear susceptibilities and skew scattering in the spin Hall effect
  • アブストラクト Abstract:
Skew scattering of electrons in metals can produce the anomalous and spin Hall effects. The microscopic mechanism is normally considered to be either the intrinsic effect of the crystal lattice or scattering from impurities, with the spin-orbit interaction in each case providing the coupling between the spin and the displacement of the electrons. As this is a relativistic effect, it is weak, and this is one of the obstacles to making and detecting spin currents. An alternative mechanism for skew scattering is from collective spin excitations in cooperatively ordered magnets and I will discuss this, with reference to specific alloys. I will discuss the effects of critical spin fluctuations in a ferromagnetic metal on anomalous and spin Hall effects as have been observed in both ferromagnetic alloys [1,2] and spin glasses [3]. As well as exploring possibilities for skew scattering this may provide probes of novel spin correlations in such materials, as the skew 
scattering is sensitive to higher order correlation functions than usually measured. I will discuss the relation to non-linear susceptibilities.

The theoretical work is in collaboration with Bo Gu and Sadamichi Maekawa, (ASRC, JAEA), Yasuhiro Niimi (U. Osaka), Yoshichika Otani (U. Tokyo), Albert Fert (Thales/CNRS) . 

[1] D. H. Wei, Y. Niimi, B. Gu, T. Ziman, S. Maekawa, and Y. Otani,' The spin Hall effect as a probe of nonlinear spin fluctuations' Nat. Commun. 3, 1058, (2012). 
[2] B. Gu, T. Ziman, S. Maekawa,  'Theory of the spin Hall effect, and its inverse, in a ferromagnetic metal near the Curie temperature', 
Physical Review B 86, 241303(R) (2013). 
[3] Y. Niimi, M. Kimata, Y. Omori, B. Gu, T. Ziman, S. Maekawa, A. Fert, and Y. Otani , 'Strong Suppression of the Spin Hall Effect in the Spin Glass State', Phys. Rev. Lett., in press (2015).