DAMAGE AND CONDUCTIVITY OF YTTRIUM-IRON-GARNET IRRADIATED WITH GEV-HEAVY IONS

Single crystals of Si-doped yttrium iron garnet (YIG:Si) have been irr adiated with 6 GeV Pb-208 ions at 80 K and 300 K The amorphization cro ss section, for a mean electronic stopping power of 35 MeV mum-1, was determined from the 300 K Fe-57 Mossbauer spectra. When going from the crystalline to the amorphous phase, the 300 K dc conductivity was fou nd to decrease versus fluence. This is interpreted by the lowering of the carrier mobility caused by disorder. Furthermore, the 300 K ac con ductivity of amorphous YIG:Si exhibited above 10 kHz an omega(alpha) l aw, with alpha congruent-to 0.8, characteristic of hopping conduction. These results are discussed with respect to undoped YIG irradiated wi th GeV heavy ions. No significant effects neither of the irradiation t emperature, nor of the electrical conductivity are observed on the dam age cross section.