The quantum-mechanical basis of an extended Landau-Lifshitz-Gilbert equation for a current-carrying ferromagnetic wire

Abstract

An extended Landau-Lifshitz-Gilbert (LLG) equation is introduced to describe the dynamics of inhomogeneous magnetization in a current-carrying wire. The coefficients of all the terms in this equation are calculated quantum-mechanically for a simple model which includes impurity scattering. This is done by comparing the energies and lifetimes of a spin wave calculated from the LLG equation and from the explicit model. Two terms are of particular importance since they describe non-adiabatic spin-transfer torque and damping processes which do not rely on spin-orbit coupling. It is shown that these terms may have a significant influence on the velocity of a current-driven domain wall and they become dominant in the case of a narrow wall.

arXiv comment19 pages, 1 figure

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Cited by in corpus (4)

• Spin-Transfer Torque in Helical Spin-Density Waves
• The absence of intraband scattering in a consistent theory of Gilbert damping in metallic ferromagnets
• First-principles calculations of current-induced spin-transfer torques in magnetic domain walls
• Unquenched orbital angular momentum as the origin of spin inertia