Perovskite oxides; dielectrics; electrical properties; X-ray diffraction; scanning electron microgra Perovskite oxides; dielectrics; electrical properties; X-ray diffraction; scanning electron microgra
Adv. Mater. Lett., 2012, 3 (2), pp 143-148
Publication Date (Web): Apr 14, 2012
Copyright © IAAM-VBRI Press
Dielectric spectroscopy is applied to investigate the electrical properties of a barium neodymium niobate, Ba(Nd0.5Nb0.5)O3 (BNN) in a temperature range from 323 K to 453 K and in the frequency range from 50 Hz to 1 MHz. The X-ray diffraction of the sample at room temperature shows a tetragonal phase. The scanning electron micrograph of the sample shows the average grain size of BNN ~ 1.92 mm. An analysis of the dielectric constant (e ¢) and loss tangent (tand) with frequency is performed assuming a distribution of relaxation times. The low frequency dielectric dispersion corresponds to DC conductivity. The logarithmic angular frequency dependence of loss peak is found to obey an Arrhenius law with activation energy of 0.55 eV. The frequency dependence of electrical data is also analyzed in the framework of conductivity and electric modulus formalisms. Both these formalisms show qualitative similarities in relaxation times. The scaling behavior of tangent loss (tanδ) suggests that the distribution of relaxation times is temperature independent in BNN.
Perovskite oxides, dielectrics, electrical properties, X-ray diffraction, scanning electron micrographs