Influence of Magnetic Anisotropy on Laser-induced Precession of Magnetization in Ferromagnetic Semiconductor (Ga,Mn)As

The laser-induced precession of magnetization in (Ga,Mn)As samples with different magnetic anisotropy was studied by the time-resolved magneto-optical method. We observed that the dependence of the precession amplitude on the external magnetic field depends strongly on the magnetic anisotropy of (Ga,Mn)As and we explain this phenomenon in terms of competing cubic and uniaxial anisotropies. We also show that the corresponding anisotropy fields can be deduced from the magnetic field dependence of the precession frequency.