Structure and electrical properties of 0.85(Bi0.5Na0.5)TiO3–0.12BaTiO3–0.03SrTiO3 ferroelectric ceramics

The crystal structure, domain structure and the electrical properties of 0.85(Bi0.5Na0.5)TiO3–0.12BaTiO3–0.03SrTiO3 ceramics have been investigated. Rietveld refinement with Fullprof software was used to analyze the X-ray diffraction data and a two-phase coexistence between a monoclinic (Cm) phase and a tetragonal phase (P4mm) best describes the diffraction patterns from 25 °C to 100 °C. Results from X-ray diffraction and dielectric measurements show that the Curie temperature is between 220 °C and 240 °C. The domain structure shows the presence of both non-180° domain walls and 180° domain walls similar to that already observed in Pb(ZrxT1−x)O3 ceramics. The hysteresis curves show that the coercive field decreases with increasing temperature up to 100 °C. The piezoelectric charge coefficient ( d 33 * ) at 25 °C is 167 ± 25 pm/V and increased only slightly with temperature up to 100 °C. These properties make this piezoelectric ceramic material suitable for ultrasonic transducers, sonars, hydrophones and other applications.