Investigation of temperature dependent electrical and impedance characteristics of bulk Zn 0.95 Co 0.05 O

Zn 0.95 Co 0.05 O was synthesized by sol-gel method and then Zn 0.95 Co 0.05 O pellet was prepared to investigate its structural, morphological, electrical, and impedance properties. For this purpose, the pellet was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and impedance measurement techniques. SEM images showed that the particle sizes of Zn 0.95 Co 0.05 O were between 1 and 100 μm. The frequency and temperature dependence of capacitance, conductance, and complex impedance characteristics of Zn 0.95 Co 0.05 O in a pellet form were investigated within the temperature range of 300–500 K and frequency range of 1 kHz–1.5 MHz. The radii of the semicircular arc reduced with increasing temperature revealing that the Zn 0.95 Co 0.05 O shows negative temperature coefficient of resistance as in semiconductors. The impedance analysis revealed the contribution of grains and grain boundaries to the conduction and polarization processes.