Magnetization reversal with domain-wall pinning in (Ga, Mn)As wire

The pinning effect of magnetic domain walls in patterned (Ga, Mn)As wires with a constriction is investigated through magnetoresistance (MR) measurements and micromagnetic simulations. An experimental MR curve of a sample with the constriction clearly demonstrates step-like magnetization behavior in its magnetization reversal process and the behavior is also observed in the calculated MR curve. Simulated magnetic domain configurations indicate that the constriction in the wire acts as an effective pinning site of a 90° domain wall.