Current Induced Order Parameter Dynamics: Microscopic Theory Applied to Co/Cu/Co spin valves

Abstract

Transport currents can alter alter order parameter dynamics and change steady states in superconductors, in ferromagnets, and in hybrid systems. In this article we present a scheme for fully microscopic evaluation of order parameter dynamics that is intended for application to nanoscale systems. The approach relies on time-dependent mean-field-theory, on an adiabatic approximation, and on the use of non-equilibrium Greens function (NEGF) theory to calculate the influence of a bias voltage across a system on its steady-state density matrix. We apply this scheme to examine the spin-transfer torques which drive magnetization dynamics in Co/Cu/Co spin-valve structures. Our microscopic torques are peaked near Co/Cu interfaces, in agreement with most previous pictures, but suprisingly act mainly on Co transition metal $d$-orbitals rather than on $s$-orbitals as generally supposed.

9 pages, 5 figures

References in corpus (3)

• First principles modeling of tunnel magnetoresistance of Fe/MgO/Fe trilayers
• Inelastic scattering in ferromagnetic and antiferromagnetic metal spintronics
• Interlayer Transport in Bilayer Quantum Hall Systems

Cited by in corpus (10)

• Spin Transfer Torques
• Ab initio studies of the spin-transfer torque in tunnel junctions
• A knitting algorithm for calculating Green functions in quantum systems
• Current-Induced Torques in Magnetic Metals: Beyond Spin Transfer
• Implementation of a non-equilibrium Green's function method to calculate spin transfer torque
• Bias dependence of magnetic exchange interactions: application to interlayer exchange coupling in spin valves
• Critical current of spin transfer torque-driven magnetization dynamics in magnetic multilayers
• Landauer theory of ballistic torkances in non-collinear spin valves
• Ballistic vs Diffusive Transport in Current-Induced Magnetization Switching
• Effect of spin diffusion on spin torque in magnetic nanopillars