Magnetocrystalline anisotropy and magnetization reversal in Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting

We report the observation of ferromagnetic resonance (FMR) and the determination of the magnetocrystalline anisotropy in (100)-oriented single-crystalline thin film samples of GaMnP with x=0.042. The contributions to the magnetic anisotropy were determined by measuring the angular- and the temperature-dependencies of the FMR resonance fields and by superconducting quantum interference device magnetometry. The largest contribution to the anisotropy is a uniaxial component perpendicular to the film plane; however, a negative contribution from cubic anisotropy is also found. Additional in-plane uniaxial components are observed at low temperatures, which lift the degeneracy between the in-plane [011] and [01-1] directions as well as between the in-plane [010] and [001] directions. Near T=5K, the easy magnetization axis is close to the in-plane [01-1] direction. All anisotropy parameters decrease with increasing temperature and disappear above the Curie temperature T_C. A consistent picture of the magnetic anisotropy of ferromagnetic GaMnP emerges from the FMR and magnetometry data. The latter can be successfully modeled when both coherent magnetization rotation and magnetic domain nucleation are considered.