STRUCTURAL AND IMPEDANCE CHARACTERISTICS OF KPb₂V₅O₁₅

Abstract

The polycrystalline sample of KPb 2 V 5 O 15 was prepared by a mixed-oxide method relatively at low temperature (i.e., 550 • C). X-ray diffraction studies of the compound showed the formation of single phase orthorhombic crystal structure at room temperature. SEM micrograph showed the homogeneous distribution of grains throughout the sample. Electric properties were analyzed using the complex impedance spectroscopy. The modulus plot showed the presence of both the grain and grain boundary effect. The bulk impedance evaluated from the Nyquist plots was observed to decrease with the rise in temperature, showing a negative temperature coefficient of resistance. The variation of AC electrical conductivity (σ AC ) was measured in a wide temperature (30-500 • C) and frequency (10 2 -10 6 Hz) range. The activation energy of the compound calculated from both the impedance and modulus spectrum was found to be the same. Int. J. Mod. Phys. B 2011.25:3745-3753. Downloaded from www.worldscientific.com by GEORGETOWN UNIVERSITY on 02/03/15. For personal use only. Int. J. Mod. Phys. B 2011.25:3745-3753. Downloaded from www.worldscientific.com by GEORGETOWN UNIVERSITY on 02/03/15. For personal use only.