THERMAL HYSTERESIS OF PHOTOINDUCED MAGNETIC EFFECT IN YTTRIUM-IRON-GARNET

In single crystals of yttrium iron garnet irradiated with laser (the m ost effective wavelength is 700 nm) or white light at 77 K, a remarkab le change of the temperature dependence of complex permeabilities mu' and mu('') is observed, which is peculiar to photoinduced magnetic eff ect. Simultaneously,conspicuous double peaks of DA around 125 K and 20 0 K below room temperature were found to be induced by light-irradiati on, with correlative onset of the irreversible decrease of permeabilit y insensitive to demagnetization at low temperature. In order to expla in these observations, we propose a new model.