Photo-Induced Precession of Magnetization in Metal/(Ga, Mn)As Systems

Photo-induced precession of magnetization in (Ga, Mn)As was studied for samples having metal (Pt and Fe) overlayers on (Ga, Mn)As epilayers. It has been found, for both structures, that an increase in the thickness of metal layers results in the reduced effective magnetic field and enhanced Gilbert damping constant. It has been shown experimentally that direct contact between metals and (Ga, Mn)As is the necessary condition to cause the observed phenomena. Spin pumping effect may be the relevant mechanism, but overall behavior is not fully explainable with simple pictures.