Growth of lead-free piezoelectric 0.45BZT-0.55BCT single crystal and investigation of dielectric, polarization and birefringence properties

Single crystals of 0.45BZT-0.55BCT were grown by spontaneous nucleation technique. The X-ray diffraction shows that grown crystals possess tetragonal symmetry with c/a =1.009. The dielectric constant shows anomalies near 109 degrees C and 2 degrees C corresponding to cubic-to-tetragonal and tetragonal-to-rhombohedral phase transitions, respectively. In addition, an abrupt non-dispersive decrease in dielectric constant was observed near 103 degrees C. Temperature dependent birefringence and remnant polarization measurement also show a sharp decrease near 103 degrees C. This anomaly in dielectric, birefringence and polarization measurements is attributed to the formation of macro-domains below 103 degrees C. Investigation under optical microscope showed that the crystals have optical birefringence similar to 0.051 and are negative uniaxial at room temperature. (C) 2013 Elsevier B.V. All rights reserved.