Dielectric relaxation in perovskite

• DOI: 10.1016/j.jpcs.2006.02.002
• Publication Date: 2006-03-30T07:52:14Z
• Authors: Alo Dutta; T.P. Sinha
• Keywords: 0103 physical sciences; 01 natural sciences

Abstract The complex perovskite oxide barium aluminium niobate, BaAl 1 / 2 Nb 1 / 2 O 3 (BAN) is synthesized by a solid-state reaction technique for the first time. The X-ray diffraction of the sample at room temperature shows a monoclinic phase. The field dependence of dielectric response and the loss tangent of the sample are measured in a frequency range from 50 Hz to 2 MHz and in a temperature range from room temperature to 623 K. An analysis of the real and imaginary parts of impedance is performed, assuming a distribution of relaxation times as confirmed by Cole–Cole plot as well as the scaling behaviour of the imaginary part of impedance spectra. This suggests that the distribution of relaxation times is temperature independent. The frequency-dependent maxima in the imaginary impedance are found to obey an Arrhenius law with an activation energy ≃ 0.49 eV . The frequency-dependent electrical data are also analysed in the framework of conductivity and electric modulus formalisms. The scaling behaviour of imaginary electric modulus shows the temperature-independent nature of the relaxation time. All these formalisms provided for qualitative similarities in the relaxation time.