Tunable magnetic anisotropy in epitaxial GaMnAs films: Evidence of temperature control

Abstract

The magnetic field dependencies of Hall resistance are studied for Ga 0.94 Mn 0.06 As/In 0.15 Ga 0.85 As film. The Hall resistance shows a slanted hysteresis cycle, emphasizing the existence of both in-plane and out-of-plane magnetization components. The anisotropy constants of the sample with out-of-plane magnetization are extracted from the angular dependence of Hall resistance measurements. The angular dependence of free magneto-crystalline energy theoretical analysis allows us to confirm the dominance of uniaxial magnetic anisotropy at specific temperatures. Here, precise angular dependence of magnetoresistance Hall Effect measurements and careful analysis using free energy model, enable us to demonstrate how the magnetic easy axis could be reoriented by the temperature within the ferromagnetic phase at the temperature far from the Curie Weiss value. This promising property will offer applicative opportunity of GaMnAs material with temperature induced transition of easy magnetization axis in detection of weak magnetic fields within the cryogenic range of low temperature phenomenon.