ELECTRICAL TRANSPORT IN DYSPROSIUM IRON-GARNET

The thermoelectric power varTheta (600舑1200 K) and electrical conductivity ॣ (500舑1200K) of Dy3Fe5O12 (Dysprosium Iron Garnet DyIG) are reported. Breaks in the slope of log ॣ vs T-1 were observed round 562 and 1000 K. Apart from these breaks, the log ॣ vs T-1 curves are linear, and their slopes correspond to activation energies of 0.72 eV (T<562 K), 0.90 eV (562舑1000 K) and 0.66 eV (T>1000 K). varTheta remains practically constant above 1000 K, but below this temperature varTheta vs T-1 is linear and can be expressed by the relation It is concluded that the charge carriers in this solid are extrinsic and conduct via the thermally-activated hopping mechanism. © 1979 The Japan Society of Applied Physics.