Light-induced changes of magnetization in single-crystal Bi-containing ferrite-garnet films

The variation of the magnetization of rare-earth ferrite garnet films of a different composition is studied in a longitudinal magnetic field at temperatures ranging from room to Curie temperatures. At relatively low temperatures, a number of films containing Lu and Yb change their magnetization as a result of a nonthermal mechanism of the action of pulsed optical radiation. A theoretical analysis reveals that the nonthermal mechanism is due to field quantities in the isotropic reverse Cotton-Mouton effect. The longitudinal relaxation time of light-induced magnetization is estimated.