Photoinduced disaccommodation in oxygen deficient yttrium iron garnet

When a single crystal of yttrium iron garnet, YIG (Ga:0.0825) with native defect of oxygen is exposed to optical light at 77 K, disaccommodation of magnetic permeability (DA) is observed to occur around 140 K and 2l0 K, as reported earlier. Furthermore, the third DA peak independent of illumination is found around room temperature in some samples, when the sample temperature is raised up to 400 K. The mechanism of these DA peaks and photoinduced irreversible decrease of initial permeability (PME)) is discussed, qualitatively, in a systematic way