Quantitative analysis of lattice distortion in Ba(Zn1/3Ta2/3)O3 microwave dielectric ceramics with added B2O3 using Raman spectroscopy

A(B′1/3B″2/3B′1/3B″2/3)O3 complex perovskites are primary candidates for microwave dielectric materials because of their high dielectric constants, very low dielectric losses, and low temperature coefficients of resonant frequency. In this study, the ordering and lattice distortion related to the cation ordering in the Ba(Zn1/3Ta2/3)O3–B2O3 system were investigated using X-ray diffraction and Raman spectroscopy. The residual stress caused by the lattice distortion associated with ordering was explained in terms of the Raman line shift. The 1:2 ordered structure of the pure BZT ceramics was replaced by a 1:1 ordered structure at 1650 °C. The addition of B2O3 improved the ordering in the BZT ceramics, and the degree of 1:2 ordering increased with increasing B2O3 content. The Raman lines of the 1:1 ordered structure were shifted towards lower wavenumbers, as compared to the disordered structures, which proves that compressive stresses were stored in the 1:1 ordered ceramics. On the other hand, in the case of the 1:2 ordered structure, the Raman lines shifted towards higher wavenumbers and the ceramics were subjected to tensile stress. The maximum Q × f value was obtained from the 1:1 ordered pure BZT ceramic sintered at 1650 °C. The Q × f value decreased with increasing B2O3 content, in spite of the highly ordered 1:2 structure.