Depinning phase transitions of current- and field-driven domain wall motion

Abstract

With the Landau-Lifshitz-Gilbert (LLG) equation, we investigate critical dynamic behaviors of the domain wall driven by the electric current and the magnetic field in disordered magnetic films. Based on the dynamic scaling form far from stationary, the critical points, and both the static and dynamic exponents of the depinning phase transition are accurately determined. The phase diagram is comprehensively depicted, which agrees with and goes beyond that of the experiments. The adiabatic and non-adiabatic spin-transfer torques induced by the electric current play distinct roles in the depinning phase transition. The novel dynamic approach to the numerical simulations of the LLG equation shows its great eciency.

Anisotropic critical behavior of current-driven skyrmion dynamics in chiral magnets with disorder

“…Disorder generally exits in magnetic materials prepared for experiments, and the insensitivity of the threshold current to the non-adiabatic coefficient and the disorder was suggested [13,26]. But such a critical current is usually dependent of the non-adiabatic coefficient in other magnetic structures, such as domain walls and helical states [13,17,43]. Our conjecture is that the insensitive behavior of skyrmions to the non-adiabatic coefficient possibly exists only in a restricted regime, and a larger non-adiabatic coefficient may effectively reduce the threshold current.…”