CHARGE-CARRIERS AND MOBILITY OF CU-TI FERRITE

The concentration and drift mobility of charge carriers in Cu1-xTixFe2O4 ferrite are calculated, over a wide range of temperatures (300-773 K), employing d.c. conductivity and thermoelectric power data. With increasing temperature the concentration of charge carriers decreases whilst the drift mobility exhibits an exponential increase. Over the above-mentioned temperature range, the obtained density of charge carriers varies between 10(21) and 10(22) cm(-3) whereas the drift mobility has values between 10(-8) and 10(-4) cm(2)/V s. The results are discussed on the basis of a small-polaron hopping conduction. The activation of the d.c. conductivity has been attributed to the thermal activation of the mobility.