Theory of superdiffusive spin transport in noncollinear magnetic multilayers
arXiv:2212.12961 · doi:10.1103/PhysRevB.107.174418
Abstract
Ultrafast demagnetization induced by femtosecond laser pulses in thin metallic layers is caused by the outflow of spin-polarized hot electron currents describable by the superdiffusive transport model. These laser-generated spin currents can cross the interface into another magnetic layer and give rise to magnetization dynamics in magnetic spin valves with noncollinear magnetizations. To describe ultrafast transport and spin dynamics in such nanostructures we develop here the superdiffusive theory for general noncollinear magnetic multilayers. Specifically, we introduce an Al/Ni/Ru/Fe/Ru multilayer system with noncollinear Ni and Fe magnetic moments and analyze how the ultrafast demagnetization and spin-transfer torque depend on the noncollinearity. We employ ab initio calculations to compute the spin- and energy-dependent transmissions of hot electrons at the interfaces of the multilayer. Taking into account multiple electron scattering at interfaces and spin mixing in the spacer layer we find that the laser-induced demagnetization of the Ni layer and magnetization change of the Fe layer strongly depend on the angle between their magnetizations. Similarly, the spin-transfer torques on the Ni and Fe layers and the total spin momentum absorbed in the Ni and Fe layer are found to vary markedly with the amount of noncollinearity. These results suggest that changing the amount of noncollinearity in magnetic multilayers one can efficiently control the hot electron spin transport, which may open a way toward achieving fast, laser-driven spintronic devices.
arXiv comment14 pages, 9 figures
References in corpus (26)
- Spin torque switching with the giant spin Hall effect of tantalum
- Spin Hall effect
- Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
- Anatomy of Spin-Transfer Torque
- Spin-Diffusion Lengths in Metals and Alloys, and Spin-Flipping at Metal/Metal Interfaces: an Experimentalist's Critical Review
- Petahertz Spintronics
- Ultrafast transport of laser-excited spin polarized carriers in Au/Fe/MgO(001)
- First-principles study of magnetization relaxation enhancement and spin-transfer in thin magnetic films
- Ab Initio Theory of Coherent Laser-Induced Magnetization in Metals
- Experimental observation of the optical spin transfer torque
- Nanoscale confinement of ultrafast spin transfer torque exciting non-uniform spin dynamics by femtosecond spin current pulses
- Picosecond Spin Orbit Torque Switching
- First-principles scattering matrices for spin-transport
- Interfacial spin-orbit torques
- Experimental observation of the optical spin-orbit torque
- Faster chiral versus collinear magnetic order recovery after optical excitation revealed by femtosecond XUV scattering
- Particle-in-cell simulation of ultrafast hot-carrier transport in Fe/Au-heterostructures
- Interface reflectivity of a superdiffusive spin current in ultrafast demagnetization and THz emission
- Robust spin-transfer torque and magnetoresistance in non-collinear antiferromagnetic junctions
- High-frequency magnon excitation due to femtosecond spin-transfer torques
- Transport theory for femtosecond laser-induced spin-transfer torques
- Domain wall dynamics due to femtosecond laser-induced superdiffusive spin transport
- Ultrafast transport and energy relaxation of hot electrons in Au/Fe/MgO(001) heterostructures analyzed by linear time-resolved photoelectron spectroscopy
- Micromagnetic view on ultrafast magnon generation by femtosecond spin current pulses
- Accelerating the laser-induced demagnetization of a ferromagnetic film by antiferromagnetic order in an adjacent layer
- Tailoring femtosecond hot-electron pulses for ultrafast spin manipulation