Temperature independent shear piezoelectric response in relaxor- PbTiO ₃ based crystals

The temperature dependence of the shear piezoelectric responses in relaxor- PbTiO₃ based perovskite crystals with rhombohedral, orthorhombic, and tetragonal phases were investigated. Based on thermodynamic analysis, high shear piezoelectric coefficients (d24) and good thermal stability were predicted in orthorhombic crystals, owing to the "vertical" orthorhombic-rhombohedral phase boundary. By resonance measurements, shear piezoelectric coefficient d24 was found to be on the order of ∼2100 pC/N at room temperature, maintaining same value over the temperature range of -50-100 °C. In contrast, the shear piezoelectric coefficients d15, with values of 3300, 3600, and 2000 pC/N at room temperature for rhombohedral, orthorhombic, and tetragonal crystals, respectively, exhibited strong temperature dependent behavior due to their respective ferroelectric-ferroelectric phase transitions.