Monitoring of magnetization processes in GaMnAs ferromagnetic film by electrical transport measurement

Abstract The transport measurement technique has been adapted to investigate the magnetization processes of GaMnAs ferromagnetic semiconductor film. While the planar Hall resistance (PHR) reached different values at 3 K in each attempt for zero field cooling (ZFC) process, it always ended the same value in the field cooling (FC) process. This indicates that the GaMnAs film in the absence of magnetic field magnetized randomly among four magnetic easy axes along 〈1 0 0〉 directions without preference of specific direction, while the presence of the magnetic field provides preference of the magnetization to specific direction. The PHR measured with and without external magnetic field in the heating process also showed significantly different behavior, which originate from the temperature dependence of magnetic anisotropy in the GaMnAs film.