X-ray diffraction, dielectric, pyroelectric, piezoelectric and Raman spectroscopy studies on (Ba0.95Ca0.05)0.8875Bi0.075TiO3 ceramic

The (Ba0.95Ca0.05)0.8875Bi0.075TiO3 ceramic composition was prepared using the conventional mixed-oxide technique. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 85 to 450 K and frequency range from 102 to 2 × 105 Hz, respectively, were studied. The X-ray spectra were investigated by profile refinement technique with the use of specialized software at room temperature, the (Ba0.95Ca0.05)0.8875Bi0.075TiO3 composition crystallizes in quadratic perovskite structure. The dielectric measurements show classical ferroelectric behavior. The pyroelectric and piezoelectric results confirm the dielectric measurements. The pyroelectric coefficient is about 69.2 nC/cm2 K at the transition temperature (TC = 367 K). The piezoelectric constant is d31 = 31.1 pC/N and the electromechanical coupling factor is kP = 0.14679. Raman spectra of (Ba0.95Ca0.05)0.8875Bi0.075TiO3 ceramic were taken at various temperatures and measured over the wave number range from 50 to 1000 cm−1. All the Raman bands were assigned as the transitional modes of Ba2+, Ca2+, Bi3+ and Ti4+ cations. The temperature evolution of Raman spectra across the transition shows an important evolution characterizing the disorder of the high temperature phase.