Abstract
In single crystals of yttrium iron garnet irradiated with white light at 77 K, a remarkable change was observed in the temperature dependence of complex permeabilities μ' and μ". Simultaneously, conspicuous double peaks of DA around 125 K (DA1) and 200 K (DA2) were found to be induced by the irradiation at 77 K, with correlative onset of an irreversible decrease of permeability at low temperature. Besides, the dark DA (DA3) independent of white-light irradiation was observed around the room temperature. The activation energy of DA (1, 2, 3) may be calculated as 0.46, 0.60, and 0.88 eV, respectively.
