Correlation between vibrational modes and structural characteristics of Ba[(Zn1−xMgx)1/3Ta2/3]O3 solid solutions

Abstract

Ba[(Zn_1−xMg_x)_1/3Ta_2/3]O₃ (BZMT, x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) solid solution ceramics were synthesized by a conventional solid-state sintering technique. Vibration spectra (Raman spectroscopy and Fourier transform far-infrared reflection spectroscopy) and X-ray diffraction (XRD) were employed to evaluate the correlation between microstructures and phonon modes of these solid solutions. Spectroscopic and structural data show sensitivity to structural evolution of samples with Mg²⁺ concentration, and a 1 : 2 ordered phase appears when x ≥ 0.2. The unit cell parameters decrease with increasing Mg²⁺ content. The ordering degree reaches a relative maximum value in the range of Mg²⁺ content, 0.4 ≤ x < 0.6. The phonon modes were assigned, and the correlation of phonon vibrations in the microstructure were analyzed. The position and width of the phonon modes were determined and correlated to the ionic radii for the different atoms substituted in the B′ -site.