Current-Assisted Domain Wall Motion in Ferromagnetic Semiconductors

We investigated the effect of electrical currents on magnetization reversal in ferromagnetic semiconductors. We fabricated a Hall bar-shaped device with a stepped channel from (Ga,Mn)As and that with a partially gated channel from (In,Mn)As. These structures realize in-plane patterning of coercivity H C and allow us to study the dynamics of domain walls under application of currents by monitoring the Hall resistance. In both devices, we show that there exists a region, where its H C is strongly influenced by the direction of the applied current. In addition, we demonstrate the current induced domain wall movement under a fixed magnetic field. These phenomena can be observed at current density of 10 4 A/cm 2 lower. Possible mechanisms are discussed.