Nonequilibrium dynamics in a spin valve with noncollinear magnetization

0564304 - FZÚ 2023 RIV US eng J - Journal Article
Smorka, R. - Baláž, Pavel - Thoss, M. - Žonda, M.
Nonequilibrium dynamics in a spin valve with noncollinear magnetization.
Physical Review B. Roč. 106, č. 14 (2022), č. článku 144435. ISSN 2469-9950. E-ISSN 2469-9969
Research Infrastructure: e-INFRA CZ - 90140
Institutional support: RVO:68378271
Keywords : dynamical phase transitions * spin dynamics * nonequlibrium systems * spin valves * tight-binding model
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.7, year: 2022
Method of publishing: Limited access
https://doi.org/10.1103/PhysRevB.106.144435

We utilize a hybrid quantum-classical equation of motion approach to investigate the spin dynamics and spin-transfer torque in a spin valve under bias voltage. We show that the interplay between localized classical magnetic moments and conduction electrons induces a complex effective exchange coupling between the magnetic layers. This leads to a declination of magnetizations from layers' anisotropy axes even in equilibrium. Introducing a finite bias voltage triggers spin currents and related spin-transfer torques which further tilt the magnetizations and govern the relaxation processes of the spin dynamics. We show that symmetric and asymmetric voltage drops can lead to relaxation times of the spin dynamics that differ by several orders of magnitude at comparable charge currents. In both cases, we observe resonant features, where the relaxation is boosted whenever the chemical potential of the leads matches the maxima in the density of the states of the spin-valve electrons.
Permanent Link: https://hdl.handle.net/11104/0336334