Magnetization dynamics driven by a jump-noise process

It is proposed to use a jump-noise process in magnetization dynamics equations to account for thermal bath effects. It is shown that in the case of a small jump-noise process, the Landau-Lifshitz and Gilbert damping terms can be analytically derived as deterministic (average) effects caused by the jump-noise process. Simple formulas for the damping constant are derived that relate it to the scattering rate of the jump-noise process and elucidate its dependence on magnetization. Generalized H-theorems for jump-noise-driven magnetization dynamics are presented. Random switching of magnetization caused by the jump-noise process is studied and it is demonstrated that the switching rate has different temperature dependence at relatively high and very low temperatures, which is traditionally attributed to the existence of phenomena of macroscopic magnetization tunneling.