DIELECTRIC-PROPERTIES AND ELECTRICAL-CONDUCTION IN YTTRIUM-IRON-GARNET (YIG)

The dielectric properties (dielectric constant and loss) of a single c rystal of yttrium iron garnet (Y3Fe5O12) were measured in the temperat ure range 77-725 K and in the frequency range 100 Hz-1 MHz. AC conduct ivity was derived from dielectric constant and loss. DC conductivity w as measured in the temperature range 30-725 K. Thermoelectric power (T EP) was measured from 77-800 K. On the basis of the results, conductio n in this garnet is interpreted as due to small polarons. The nature o f conduction at different temperature ranges is discussed in the light of existing reports on defect formation.