On computation of relaxation constant α in Landau–Lifshitz–Gilbert equation

Due to the quasi-classical kinetic equation (QKE) for the magnon distribution function to calculate the velocity of the domain wall motion V in magnetic fields H>H_a, where H_a− magnetic anisotropy field. Based on the comparison of this formula for Vthe analytic expression of relaxation constant α in Landau–Lifshitz–Gilbert equation was found. We used the detected correlation between the system's entropy and the environment's resistance force, and obtained an expression for the spin-lattice braking force that is applied to the moving domain wall. We calculated the mobility ratio of the domain wall. - Highlights: • The resistance force acting on the domain wall was calculated. • Mobility coefficient of domain wall was calculated. • The strict calculation of relaxation constant in equation Landau-Lifshitz- Gilbert