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Gauge Field Formulation of Adiabatic Spin Torques

Hiroshi Kohno·Junya Shibata
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Abstract

Previous calculation of spin torques for small-amplitude magnetization dynamics around a uniformly magnetized state [J. Phys. Soc. Jpn. {\bf 75} (2006) 113706] is extended here to the case of finite-amplitude dynamics. This is achieved by introducing an `` adiabatic'' spin frame for conduction electrons, and the associated SU(2) gauge field. In particular, the Gilbert damping is shown to arise from the time variation of the spin-relaxation source terms in this new frame, giving a new physical picture of the damping. The present method will allow a `` first-principle'' derivation of spin torques without any assumptions such as rotational symmetry in spin space.

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Hiroshi Kohno, Junya Shibata. 2007-03-27. Gauge Field Formulation of Adiabatic Spin Torques. https://doi.org/10.1143/jpsj.76.063710

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