Spin wave amplification in antiferromagnetic semiconductors stimulated by infrared laser field

The spin wave excitation induced by infrared laser radiation in antiferroma gnetic semiconductors is considered. By considering that several photons fr om the IR laser field can be involved in the electronic transition a kineti c equation for the magnon population is calculated from which the magnon ex citation rate is calculated. It is found that under certain conditions the excitation rate may become greater than the magnon relaxation rate and the magnon system can reach instability. An application is made for the antifer romagnetic semiconductor EuTe. (C) 2001 Elsevier Science B.V. All rights re served.