Photoinduced Faraday rotation in the magnetic semiconductor CdCr2Se4

Abstract

A growth of the excitonic peak in the absorption spectrum and an enhancement of the Faraday rotation band (approximately 50% of the linear effect value) were induced by intensive radiation of Nd 3+ -laser (hν = 1.17 eV) in ferromagnetic phase of magnetic semiconductor CdCr 2 Se 4 . The photoinduced effects increased during a pumping pulse and also with growth of pump intensity. In studies of the non-linear Faraday rotation a change of the spectral band shape was observed along with the growth of the rotation angle. The observed effects can be explained by the screening of internal electric fields existing in CdCr 2 Se 4 crystals by photoexcited charge carriers.