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 (d33*) 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.