ELECTRICAL-CONDUCTIVITY OF LI-TI FERRITES

Both, de and ac conductivities of the Li-Ti ferrite system with chemic al formula Li0.5+0.5xTizFe2.5-1.5xO4 for 0 less than or equal to x les s than or equal to 0.7 were measured at room temperature and elevated temperatures up to 833 Ii. The ac conductivity was measured in the fre quency range from 100 Hz to 100 kHz. A strange behavior was observed a nd two regions appear in the conductivity-temperature dependence. The low-temperature range, region I, was attributed to impurity conduction in addition to an effective carrier-phonon interaction. A hopping con duction mechanism was considered for the conduction in region II. The hopping threshold energy corresponding to T-m, the temperature at whic h a minimum in conductivity occurs, was determined. The hopping energy Delta w), the exponential frequency parameter (S) and the phonon freq uency (v(p)) were estimated.