Annotation

V.D.Lakhno, E.L.Nagaev.
Nondissipative photoferromagnetism of magnetic semiconductors //Zh. Eksp. Teor. Fiz., 1978, v.74, №6, p.2123-2130

      A theory is developed of a change in the magnetization of ferromagnetic semiconductors as a result of illumination. In contrast to the usual situation when the frequency of light lies within an absorption band, an analysis is made of the frequency range in which a crystal is transparent. In this case the photoferromagnetic effect is due to virtual transitions of electrons from the valence to the conduction band. Such transitions result in the mixing of the conduction- and valence-band states. This mixing enhances the exchange of electrons between the valence bands and localized d or f magnetic moments, and thus facilitates the establishment of the ferromagnetic order. The situation is treated as a nonlinear kinetic problem. An expression is obtained for the shift of the magnon frequency in the spin-wave range. Extrapolation of the calculated results to higher temperatures makes it possible to estimate the shift of the Curie temperature.