THE THERMOELECTRIC-POWER OF FERROMAGNETICALLY ORDERED CU1-XGAXCR2SE4 SPINELS

Single crystals of Cu1-xGaxCr2Se4 have been prepared using a chemical vapor method. The absolute thermoelectric power S and the electrical r esistivity rho of single crystals with compositions x = 0.036, 0.158, 0.374, 0.394, have been measured in the temperature range from 5 to 40 0K. All compounds are p-type metallic conductors with the residual res istance increasing with increasing gallium concentration. The temperat ure dependence of the resistivity is almost constant for temperatures T<T-c and increases close to the Curie temperature T-c, indicating a s pin scattering contribution. A broad hump Delta S(T) which goes to zer o close to T-c apparently is superimposed on a linear diffusion thermo power, suggesting magnon drag.