Photoinduced Magnetization Rotation and Precessional Motion of Magnetization in Ferromagnetic (Ga,Mn)As

Abstract

Dynamics of photoinduced magnetization have been studied in ferromagnetic semiconductor (Ga,Mn)As thin films by time-resolved polar Kerr rotation. Ultrafast (∼150 fs) magnetization rotation has been realized using both chirality of excitation light and p–d exchange interaction. We also report on the occurrence of photoinduced magnetization precession in longer time domain. This is initiated by a change in hole concentration and resultant change in magnetic anisotropy. The overall behaviors of these photoinduced magnetization dynamics are discussed.