Dielectric and modulus behavior of LiFe1/2Ni1/2VO4 ceramics

The polycrystalline sample of LiFe1/2Ni1/2VO4 was prepared by a standard solid-state reaction technique and confirmed by X-ray diffractometry. LiFe1/2Ni1/2VO4 has orthorhombic crystal structure whose dielectric and electric modulus properties were studied over a wide frequency range (100 Hz–1 MHz) at different temperatures (296–623 K) using a complex impedance spectroscopy (CIS) technique. The frequency and temperature dependence of dielectric constant (εr) and tangent loss (tan δ) of LiFe1/2Ni1/2VO4 are studied. The variation of εr as a function frequency at different temperatures exhibits a dispersive behavior at low frequencies. The variation of the εr as a function of temperature at different frequencies shows the dielectric anomaly in εr at 498 K with maximum value of dielectric constant 274.49 and 96.86 at 100 kHz and 1 MHz, respectively. Modulus analysis was carried out to understand the mechanism of the electrical transport process, which indicates the non-exponential type of conductivity relaxation in the material. The activation energy calculated from electric modulus spectra is ∼0.38 eV.