SKM 2023 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Spin Transport and Orbitronics, Spin-Hall Effects (joint session MA/TT)
MA 4.3: Vortrag
Montag, 27. März 2023, 10:00–10:15, HSZ 403
Nonequilibrium dynamics in a spin valve with noncollinear magnetization — •Rudolf Smorka1, Pavel Baláž2, Michael Thoss1, and Martin Žonda3,1 — 1University of Freiburg, Germany — 2Institute of Physics of the Czech Academy of Sciences Prague, Czech Republic — 3Charles University Prague, Czech Republic
Manipulation of magnetization by electric currents enables novel functions for spin-transfer torque devices. We study the nonequilibrium spin dynamics and spin-transfer torques in noncollinear spin-valve heterojunctions using a mixed quantum-classical Ehrenfest approach.
In an isolated valve for short spacer layers and weak spin-electron couplings, magnetization dynamics of the ferromagnetic layers is in agreement with the macrospin approximation. For large spacer layers, our quantum-classical approach predicts electron-induced spin relaxation. For intermediate electron-spin couplings, a change in the localization character of the electronic eigenstates from metallic-like to insulator-like leads to a reduced indirect exchange interaction between spins mediated by the conduction electrons. In a spin valve coupled to leads, spin relaxation times differ by several orders of magnitude depending on whether the DC bias is introduced by shifting the electrochemical potentials of both leads symmetrically about the equilibrium Fermi level of the spin valve (reminiscent of a gate-tunable junction) or by shifting the chemical potential of only one lead (as realized in a scanning tunneling microscope geometry).
[1] R. Smorka, P. Baláž, M. Thoss, M. Žonda, Phys. Rev. B 2022, 106, 144435.