THERMAL SPECTRUM OF PHOTOINDUCED DISACCOMMODATION IN YTTRIUM-IRON-GARNET

A remarkable change of the temperature dependence of complex permeabil ities mu' and mu '' is observed in single crystals of yttrium iron gar net irradiated with an intense visible light at 77 K. Conspicuous doub le peaks of photoinduced disaccommodation (DA) around 130 K(DA(I)) and 200 K (DA(II)), with correlative onset of the irreversible decrease o f mu' at low temperature were found. Estimated activation energies of these peaks are 0.46 eV for DA(I) and 0.7 eV for DA(II). In addition, we observed the third peak (DA(III), 0.88 eV) independent of irradiati on around the room temperature. The estimated height of potential barr ier around oxygen vacancy is 0.3 eV. A simple model for the explaining these results is presented here.