THE THERMOELECTRIC-POWER OF FERROMAGNETICALLY ORDERED CU1-XGAXCR2SE4 SPINELS

The absolute thermoelectric power and the electrical resistivity of Cu 1-xGaxCr2Se4 spinel single crystals have been measured in [001] direct ion and in the temperature range from 5 to 400 K and for compositions between x=0.036 and x=0.394. The above investigations showed that all compounds under study are p-type metallic conductors. It was also obse rved that the thermoelectric power can be explained considering only t he diffusion component (which varies linearly with temperature) and a magnon drag contribution. The positive slope of the linear part of the rmopower decreases with decreasing Ga concentration. The thermoelectri c power of the sample with x=0.036 does not depend on temperature for T >200 K. These effects are explained in terms of spin- and alloy-scat tering processes including non-stoichiometry.