Electrical conductivity and thermoelectric power of Cu-Ti ferrite

The electrical conductivity and thermoelectric power have been measured in the temperature range 300 to 773 K for a series of mixed Cu-Ti ferrites, Cu1-xTixFe2O4 with x = 0-0.5. It is found that all the compositions of the series behave as n-type semiconductors in the measured range of temperature. The conduction mechanism is discussed on the basis of a small polaron hopping model. The activation energy from the conductivity data, E-sigma, is found to be higher than that calculated from the thermoelectric power, E-F. The discrepancy between E-sigma and E-F is evidence for the existence of thermally activated hopping in the ferrite system. (C) 1998 Elsevier Science S.A. All rights reserved.