Photoinduced Irreversible Effects on Magnetic Properties and Allied Phenomena in Magnetic Oxides VI

Photoinduced variation of magnetic complex permeabilities μ\u27 and μ" as a function of temperature or time is reviewed in yttrium iron garnet which has been studied in our laboratories. Our basic idea is; when the oxygen vacancies are made empty by photoexcitation, the resulting perturbation is larger than when this vacancy has one or two electrons. New data and the further discussion based on the localized and band model are also described

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 VII

Photoinduced irreversible change in an optical absorption α was observed for a bulk single crystal and a thin film of yttrium-iron garnets (YIG) over the spectral range 600 or 700-2000nm and over the temperature range 80-200K. The observation is discussed based on a local structural change induced by an irradiation

PHOTOINDUCED IRREVERSIBLE EFFECTS ON MAGNETIC PROPERTIES AND ALLIED PHENOMENA IN MAGNETIC OXIDES XII [Review]

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 yttrium iron garnet, which is irradiated with laser (the most effective wavelength is 700nm) or white light at 77K. And these results are limited to development in our laboratories, although the important contribution by many researchers cannot be excluded to the phenomena. Then, a remarkable change of the temperature dependence of complex permeabilities μ"and is observed, which is specific to photoinduced magnetic effect. New results of dark disaccommodation are also described in relation to loading impact, which is as yet not published. These origin has been discussed on the basis of new concept, that is, photoinduced structure change

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