Thermokinetic approach of the generalized Landau-Lifshitz-Gilbert equation with spin-polarized current

In order to describe the recently observed effect of current induced magnetization reversal in magnetic nanostructures, the thermokinetic theory is applied to a metallic ferromagnet in contact with a reservoir of spin-polarized conduction electrons. The spin-Rip relaxation of the conduction electrons is described thermodynamically as a chemical reaction. In the two-current approximation, the diffusion equation of the chemical potential, the giant magnetoresistance at the interface, and the usual Landau-Lifshitz-Gilbert (LLG) equation is obtained from the entropy variation in the absence of current. The description of the conservation laws, including spin dependent scattering and spin injection, leads to the derivation of a generalized LLG equation. The equation is applied to the measurements obtained on single magnetic Ni nanowires.