セミナー案内

日時
    
5月24日 (水), 13:30-
場所
京都大学理学部 5号館 413
講演者
Ms. Rina Takashima
(Condensed Matter Theory Group)
タイトル
"Manipulation of magnetic moment by supercurrent"
備考欄 (アブストラクト等)

Abstract:
Applications of superconductivity offer new possibilities in spintronics[1]. Spin valves using superconductors show colossal magnetoresistance effects, and the lifetime of spin density is enhanced in a superconducting state relative to a normal state. While interesting aspects of spintronics with the proximity-induced superconductivity have been reported, it is not well understood how a supercurrent acts on magnetic moments.
We study spin transfer torques (STT) induced by a spin-triplet supercurrent in a magnet with the superconducting proximity effect [2]. STT have attracted much attention for controlling magnetization by applied currents, and the magnetization dynamics sensitively depends on the direction of STT. By a perturbative approach, we show that spin-triplet correlations realize a new type of torque, which is analogous to the adiabatic and non-adiabatic torques. We demonstrate that this torque realizes an efficient manipulation of a domain wall.
If time allows, I will also talk on (a) Spin-orbit torques and quasi-particle structure in a chiral magnet with singlet superconductivity[3], (b) Supercurrent induced noncollinear magnetic order.


Reference:
[1] e.g., J. Linder and J. W. A Robinson, Nat. Phys. 11, 307 (2015)
[2] RT, S. Fujimoto, and T. Yokoyama (to be submitted)
[3] RT and S. Fujimoto, Phys. Rev. B 94, 235117 (2016)