A selfconsistent theory of current-induced switching of magnetization

Abstract

A selfconsistent theory of the current-induced switching of magnetization using nonequilibrium Keldysh formalism is developed for a junction of two ferromagnets separated by a nonmagnetic spacer. It is shown that the spin-transfer torques responsible for current-induced switching of magnetization can be calculated from first principles in a steady state when the magnetization of the switching magnet is stationary. The spin-transfer torque is expressed in terms of one-electron surface Green functions for the junction cut into two independent parts by a cleavage plane immediately to the left and right of the switching magnet. The surface Green functions are calculated using a tight-binding Hamiltonian with parameters determined from a fit to an {\it ab initio} band structure.This treatment yields the spin transfer torques taking into account rigorously contributions from all the parts of the junction. To calculate the hysteresis loops of resistance versus current, and hence to determine the critical current for switching, the microscopically calculated spin-transfer torques are used as an input into the phenomenological Landau-Lifshitz equation with Gilbert damping. The present calculations for Co/Cu/Co(111) show that the critical current for switching is $\approx 10^{7}A/c{m}^2$, which is in good agreement with experiment.

23 pages, 16 figures

References in corpus (8)

• Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
• Current-driven Magnetization Reversal and Spin Wave Excitations in Co/Cu/Co Pillars
• Anatomy of Spin-Transfer Torque
• Mechanisms of spin-polarized current-driven magnetization switching
• Field dependence of magnetization reversal by spin transfer
• Ground-State Phase Diagram of Quantum Heisenberg Antiferromagnets on the Anisotropic Dimerized Square Lattice
• Current driven switching of magnetic layers
• Theory of Current-Induced Magnetization Precession

Cited by in corpus (27)

• Spin Transfer Torques
• Microscopic approach to current-driven domain wall dynamics
• Anomalous Bias Dependence of Spin Torque in Magnetic Tunnel Junctions
• Switching Distributions for Perpendicular Spin-Torque Devices within the Macrospin Approximation
• Microscopic Calculation of Spin Torques in Disordered Ferromagnets
• Spin-transfer torques in anti-ferromagnetic metals from first principles
• Threshold Current of Domain Wall Motion under Extrinsic Pinning, $\beta$-Term and Non-Adiabaticity
• Spin-transfer torque and spin-polarization in topological-insulator/ferromagnet vertical heterostructures
• Current Induced Order Parameter Dynamics: Microscopic Theory Applied to Co/Cu/Co spin valves
• Spin Transfer Torque in Antiferromagnetic Spin-Valves: From Clean to Disordered Regimes
• Implementation of a non-equilibrium Green's function method to calculate spin transfer torque
• Field- and damping-like spin-transfer torque in magnetic multilayers
• A numerical method to solve the Boltzmann equation for a spin valve
• Detection of spin reversal and nutations through current measurements
• Voltage Dependence of Spin Transfer Torque in Magnetic Tunnel Junctions
• Subnanosecond switching of local spin-exchange coupled to ferromagnets
• Critical current density for spin transfer torque switching with composite free layer structure
• Tailoring femtosecond hot-electron pulses for ultrafast spin manipulation
• Magnetization reversal driven by spin-injection : a mesoscopic spin-transfer effect
• Landauer theory of ballistic torkances in non-collinear spin valves
• A Scattering method to the equilibrium spin current in a ferromagnet junction
• Spin Transfer Torque and Tunneling Magnetoresistance Dependences on the Finite Bias Voltages and Insulator Barrier Energy
• Ballistic vs Diffusive Transport in Current-Induced Magnetization Switching
• A microscopic model for current-induced switching of magnetization for half-metallic leads
• Theory of Spin-Transfer Torque in the Current-in-Plane Geometries
• New mechanism for generating spin transfer torque without charge current
• Spin Transfer Torque in Domain Wall Structures by Keldysh Green Functions