Thermally Stable BaTiO ₃ ‐Bi(Mg _2/3 Nb _1/3 )O ₃ Solid Solution with High Relative Permittivity in a Broad Temperature Usage Range

Abstract

A combined X‐ray diffraction (XRD), Raman spectra, X‐ray photoelectron spectroscopy, Scanning electron microscopy, and dielectric characterization of (1– x ) BaTiO 3 − x Bi ( Mg 2/3 Nb 1/3 ) O 3 ceramic system were investigated for compositions of 0 ≤ x ≤ 0.2. Single‐phase perovskite‐type XRD patterns were observed for all compositions. A systematically structural change from tetragonal to pseudocubic symmetry occurred at 0.04 < x < 0.06, which agrees well with the analysis of Raman spectra. Dielectric measurements indicated that the crossover from a classic ferroelectric to relaxor ferroelectric occurred at x ≥ 0.04. Compared with other compositions, the temperature independence of relative permittivity at T > T m significantly ameliorated at x = 0.1: near‐stable temperature coefficient of higher relative permittivity (~6800 ± 15%) and the corresponding loss tanδ ≤ 0.09 over a more broader temperature range of 25°C–240°C (1 kHz), which indicates that this ceramic is a promising dielectric material for elevated temperature dielectrics.