OPTICAL-PROPERTIES OF YTTRIUM-IRON-GARNET IRRADIATED WITH HIGH-ENERGYHEAVY-IONS

The damage induced in yttrium iron garnet (YIG) epilayers by high-ener gy heavy ions, in the electronic stopping power regime, has been monit ored by optical absorption spectroscopy in the visible range. The late nt track radii obtained from such data are compared with previous dete rminations based on saturation magnetization measurements and channell ing RBS data. An optical gap shrinkage of about 1 eV is found in the d isordered phase compared to the crystal. However, no variation of the refractive index is seen. These data are discussed with respect to the local atomic structure of disordered YIG.