Dielectric and modulus studies on LiFe1/2Co1/2VO4

LiFe1/2Co1/2VO4 was prepared by a standard solid-state reaction method and identified by X-ray diffractometry. LiFe1/2Co1/2VO4 has orthorhombic crystal structure whose dielectric and electric modulus properties were studied over a range of frequency (100 Hz to 1 MHz) and temperature (299–673 K) using ac technique of complex impedance spectroscopy (CIS). Experimental results show that variation of dielectric constant (ɛr) as a function frequency at different temperatures exhibit a dispersive behavior at low frequencies. The variation of the ɛr as a function of temperature at different frequencies shows that the transition temperature (Tc) shifts from 598 to 673 K with decrease in ɛr on changing frequency from 1 kHz to 1 MHz. Dielectric loss (tan δ) was also studied over the frequency and temperature ranges. Modulus analysis has been carried out to understand the mechanism of electrical transport process and this indicated non-exponential type conductivity relaxation in the material. The activation energy calculated from electric modulus spectra is ∼0.34 eV.