Current-Assisted Domain Wall Motion in Ferromagnetic Semiconductors

Abstract

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 HC 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 HC 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 104 A/cm2 lower. Possible mechanisms are discussed.