Synthesis, electrical and thermal properties of Bi₄V_2−xZr_xO₁₁ (x = 0.0, 0.02, 0.06 and 0.10) ceramics

Polycrystalline ceramic samples of Bi₄V_2−xZr_xO₁₁ (x = 0.0, 0.02, 0.06 and 0.10) have been synthesized by standard solid state reaction method using high purity oxides. The formation of the compounds have been checked by X-ray diffraction method. The dielectric constant, dielectric loss and ac conductivity as a function of frequency and temperature have been measured. The dielectric studies indicate that the material is highly lossy and hence its ac conductivity increases with the increase of temperature. The dc conductivity of all the materials has been measured as a function of temperature from room temperature to 673 K and its activation energy was calculated using the relation σ = σ_oexp (−Ea/kT). The Modulated Differential Scanning Calorimetry (MDSC) has been used to investigate the effect of substitution on the heat capacity and heat flow of the compounds. The results are discussed in detail.