Thermally Stable BaTiO3-Bi(Mg2/3Nb1/3)O3 Solid Solution with High Relative Permittivity in a Broad Temperature Usage Range

A combined X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy, Scanning electron microscopy, and dielectric characterization of (1-x)BaTiO3-xBi(Mg2/3Nb1/3)O-3 ceramic system were investigated for compositions of 0x0.2. Single-phase perovskite-type XRD patterns were observed for all compositions. A systematically structural change from tetragonal to pseudocubic symmetry occurred at 0.04<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 x0.04. 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 (similar to 6800 +/- 15%) and the corresponding loss tan0.09 over a more broader temperature range of 25 degrees C-240 degrees C (1kHz), which indicates that this ceramic is a promising dielectric material for elevated temperature dielectrics.