Structural and Electrical Properties of Lead-Free Perovskite Ba(Al_(1/2)Nb_(1/2))O_3

摘要

Lead-free perovskite Ba(Al_(1/2)Nb_(1/2))O_3 was prepared by conventional ceramic fabrication technique at 1350℃/5 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. X-ray diffraction analysis of the compound indicated the formation of a single-phase monoclinic structure with the space group P2/m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Permittivity data showed low-temperature coefficient of capacitance (T_(CC) = 14%) up to 100℃. 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. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier-hopping model was used to successfully explain the mechanism of charge transport in Ba(Al_(1/2)Nb_(1/2))O_3.