Impedance analysis and high temperature conduction mechanism of flux grown Pb(Zn1/3Nb2/3)0.91Ti0.09O3 single crystal

The electrical properties of Pb(Zn-1/3 Nb-2/3)(0.91)Ti0.09O3 single crystals over a wide range of frequencies (20 Hz to 2 MHz) and temperature (30 to 490 degrees C) were studied using impedance spectroscopic technique. A strongly frequency dependant Debye type relaxation process in crystals was observed. The activation energy for relaxation was found to be 1.72 eV. The nature of Cole-Cole plot reveals the contribution of only grain (bulk) effect in the sample. The temperature dependant conductivity was found to different in different temperature regions, which shows the presence of different carrier for conduction. The activation energy for conduction in the order of 1.69 eV suggested that the conduction process in higher temperature region is governed by the presence of lead vacancy defect in the sample. Further, the negative temperature thermistor behaviour of the system was explored and various associated parameters were calculated. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim