Temperature and Frequency Dependence Electrical Properties of Zn1-xCaxO Nanoceramic
T. Das, B.K. Das, K. Parashar and S.K.S. Parashar
Centre for Nanotechnology, School of Applied Sciences, KIIT University, Bhubaneswar-751024, Odisha, India
Received: March 17, 2016; In final form: November 18, 2016
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This work reports the temperature and frequency dependence electrical properties of Ca doped ZnO (Zn1-xCaxO, x=0.01) nanoceramic synthesized by solid state reaction method. The X-ray spectra show that the synthesized powder has hexagonal wurtzite structure with space group P63mc. The average crystallite size decreases with Ca doping. The increase in oxygen positional parameter (u) indicates lattice distortion in the crystal structure. Doping with Ca caused a slight shift in the (101) plane peak towards lower diffraction angle. The formation of pores in field emission scanning electron microscopy micrograph may be due to the defect created by Ca substitution. The electrical property was investigated by impedance spectroscopy in the temperature range 300-500°C. The synthesized sample shows temperature dependence relaxation phenomena and negative temperature coefficient of resistance effects. Electrical conductivity (σac) increases with increase in temperature as well as with frequency due to the drift mobility of electrons and hole by hopping conduction. Dielectric constant was found to decrease with increase in frequency and temperature. This decreases drastically in the magnitude of approximately < 10 times than the corresponding undoped one.

DOI: 10.12693/APhysPolA.130.1358
PACS numbers: 61.05.cP, 68.37.xy, 84.37.+q, 72.80.Lc, 77.22.Ch