Evaluation of the Ultrafast Thermal Manipulation of Magnetization Precession in Ferromagnetic Semiconductor (Ga,Mn)As.

We present a quantitative evaluation study of the thermal effect responsible for laser-triggered collective magnetization dynamics in a ferromagnetic (Ga,Mn)As film without applying the external magnetic field by employing the pump-probe magneto-optical spectroscopy. Our observation shows that the effect of ultrafast laser heating on the manipulation of magnetization precession in a (Ga,Mn)As film is not exactly equivalent to that of the ambient temperature increase, and needs to be carefully analyzed by considering the temperature-dependent specific heat of (Ga,Mn)As. The transient modulation of magnetocrystalline anisotropy via ultrafast laser heating at low temperature exhibits a higher sensitivity than that at high temperature. The quantitative analysis of the laser-heating manipulated magnetization precession presented in this work is helpful for evaluating the laser-triggered ultrafast magnetization dynamics in (Ga,Mn)As films. [ABSTRACT FROM AUTHOR]