Mechanism of Temperature Dependence of Piezoelectric Properties for Pb(Zr, Ti)O3

Temperature dependence of piezoelectric properties was measured for a tetragonal and a rhombohedral Pb(Zr, Ti)O3 (denoted as t-PZT and r-PZT, respectively). A least squares fitting of complex admittance data was employed in order to precisely determine various electromechanical constants. It was confirmed that the piezoelectric constant d 31 of the t-PZT was thermally stable while that of the r-PZT largely increased with temperature. It was clarified that the elastic compliance s 11 E and the electromechanical coupling factor k 31 decreased and the dielectric constant ε33 T increased with temperature in the t-PZT, giving rise to the thermally stable behavior of d 31. In the case of the r-PZT, the increase in ε33 T dominated the temperature dependence of the d 31. From the XRD analysis, it seemed that the increase in ε33 T of the r-PZT originated from a large thermal expansion of the unit cell volume.