Spin–Orbit-Induced Effective Magnetic Field in GaMnAs Ferromagnetic Semiconductor

Spin-orbit-induced (SOI) field of crystalline GaMnAs ferromagnetic film has been investigated by using planar Hall effect measurements. The presence of SOI field manifested itself as an asymmetry in the magnetization reversal process between positive and negative current directions. A significant Joule heating caused by current has been observed and its effect was carefully considered to obtain the magnetic anisotropy of the GaMnAs film. The switching of magnetization by SOI field in the GaMnAs film was demonstrated in the absence of an external field.