Ba sub(0.06)(Na sub(1/2)Bi sub(1/2)) sub(0.94)TiO sub(3)-Ba(Fe sub(1/2)Ta sub(1/2))O sub(3): giant permittivity lead-free ceramics

• Published in: Journal of materials science. Materials in electronics Vol. 28; no. 6; pp. 4763 - 4771
• Main Authors: Roy, Sumit K, Singh, S N, Mukherjee, S K, Prasad, K
• Format: Journal Article
• Language: English
• Published: 01.03.2017
• Subjects: Ceramics; Dielectric constant; Dielectrics; Formations; Lead free; Permittivity; Phase transformations; X ray diffraction
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-6121-x

Perovskite type lead-free (1 - x)Ba sub(0.06)(Na sub(1/2)Bi sub(1/2)) sub(0.94)TiO sub(3)-x Ba(Fe sub(1/2)Ta sub(1/2) )O sub(3) (0 less than or equal to x less than or equal to 1.0) ceramics have been synthesized using solid-state reaction method and characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman spectroscopy and dielectric studies. X-ray diffraction studies of all the ceramics suggested the formation of single phase with crystal structure transforming from rhombohedral-tetragonal (R3c) to hexagonal (P3m1) symmetry with the increase in Ba(Fe sub(1/2)Ta sub(1/2))O sub(3)-content. Raman and FTIR spectra also confirmed the formation of single phase solid solutions. Dielectric studies showed the giant permittivity ~10 super(6) in x = 0.50 and 0.75 compositions and the phase transition is found to be of diffusive character. The simultaneous occurrence of compositional fluctuations and weak ferroelectric interactions were considered to be the main cause for diffusivity.