Electrical properties of BaY_(0.5)Nb_(0.5)O_3 ceramic: Impedance spectroscopy analysis

摘要

Lead-free perovskite BaY_(0.5)Nb_(0.5)O_3 was prepared by conventional ceramic technique at 1375 °C/7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were derived from the experimental results using FullProf software. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm3m. EDAX, X-ray mapping and SEM studies were carried to study the quality and purity of the compound. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. To find a correlation between the response of the real system and idealized model circuit composed of discrete electrical components, the model fittings were presented using the impedance data. Electric modulus studies supported the hopping type of conduction in BaY _(0.5)Nb_(0.5)O_3. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in BaY_(0.5)Nb_(0.5)O_3. The ac conductivity data were used to evaluate the density of states at Fermi level, minimum hopping length and apparent activation energy of the compound.