*Department of Health Services Administration, Graduate School of Public Health, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico; †Cancer Control and Population Sciences Program, University of Puerto Rico Comprehensive Cancer Center, San Juan, Puerto Rico; ‡Department of Biostatistics and Epidemiology, Graduate School of Public Health, University of Puerto Rico Medical ...

The influence of irradiation with white light on the permeability at 77 K is investigated on p-type yttrium iron garnet single crystals with Pb impurity. Theexistence of an irreversible photo-magnetic effect and photo-accelerated disaccommodation is demonstrated in p-type YIG. These effects are explained by a modified two center model in which Fe4+ plays an important role.