Magneto-optical and micromagnetic simulation study the current driven domain wall motion in ferromagnetic (Ga,Mn)As

摘要

We have studied current-driven domain wall motion in modifiedGa_0.95Mn_0.05As Hall bar structures with perpendicular anisotropy by usingspatially resolved Polar Magneto-Optical Kerr Effect Microscopy andmicromagnetic simulation. Regardless of the initial magnetic configuration, thedomain wall propagates in the opposite direction to the current with criticalcurrent of 1~2x10^5A/cm^2. Considering the spin transfer torque term as well asvarious effective magnetic field terms, the micromagnetic simulation resultsare consistent with the experimental results. Our simulated and experimentalresults suggest that the spin-torque rather than Oersted field is the reasonfor current driven domain wall motion in this material.