Thermally activated dynamics of current-driven skyrmions in random media

Abstract

Based on the Landau-Lifshitz-Gilbert equation, we perform large-scale numerical simulations of the skyrmion dynamics with quench disorder at finite temperatures. Two universal creep behaviors are observed below the depinning transition current, and the creep exponents are accurately determined. The thermal rounding exponents at the depinning transition indicate an anisotropic temperature dependence in the perpendicular and parallel directions of the current. Further, the temperature-current phase diagram of the skyrmion Hall angle is builded, and the thermally activated forces are analyzed. Our results provide comprehensive understanding for the role of temperature in the current-driven skyrmion dynamics.