PHOTOINDUCED IRREVERSIBLE EFFECTS ON MAGNETIC PROPERTIES AND ALLIED PHENOMENA IN MAGNETIC OXIDES IX

In single crystals of yttrium iron garnet irradiated with laser (the most effective wavelength is 700nm) or white light at 77K, a remarkable change of the temperature dependence of complex permeabilities μ′ and μ″ is observed, which is peculiar to photoinduced magnetic effect. Simultaneously, conspicuous double peaks of DA around 125K and 200K below room temperature were found to be induced by light-irradiation, with correlative onset of the irreversible decrease of permeability insensitive to demagnetization at low temperature. The height of potential barrier around oxygen vacancy may be estimated 0.3eV. In order to explain these observations, we propose that oxygen defects provide a mechanism for occurrence of photomagnetic effects and discuss its validity; the review of these area of our laboratory in 1996 is given

Photoinduced Irreversible Effects on Magnetic Properties and Allied Phenomena in Magnetic Oxides. I

This is a survey of the photoinduced irreversible effects and related phenomena in magnetic oxides, mainly YIG. Although several pictures on these phenomena and an plausible explanation have been proposed, these have not been established as yet. This survey will concentrate on the authors\u27 experiments and pictures of these subjects, rather than the other researcher\u27s. This is roughly divided into the four separate parts; I. Experimental, II. Photoinduced irreversible permeability effect, III. Allied phenomena, IV. Conclusive discussion

PHOTOINDUCED IRREVERSIBLE EFFECTS ON MAGNETIC PROPER TIES AND ALLIED PHENOMENAIN MAGNETIC OXID ES XI

A review is presented of the various experimental results that have thus far been developed for the study of disaccommodation (DA) in a single crystals of y ttrium iron garnet in 1998,which is irradiated with laser (the most effective wavelength is 700 nm) or white light at 77K. Then, a remarkable change of the temperature dependence of complex permeabilities and is observed, which is specific to photoinduced magnetic effect. Simultaneously, conspicuous double peaks of DA around 125 K and 250 K below room temperature were found to be induced by light-irradiation, with correlative onset of the irreversible decrease of permeability sensitive to demagnetization at low temperature. Furthermore, photoinduced Accommodation is observed in this sample at comparatively high frequency for the first time. In addition, three peaks of (DA) in poly cry stalline CaVIn-garnet have been for the first time observed, double peaks. in order to explain these observations, we propose that oxygen defects provide a mechanism for occurrence of photomagnetic effects and discussion of its validity; the review of these area of our laboratories in 1998 is given. On the basis of these results a model for the photoinduced magnetic after effects of YIG is proposed and discussed