Shear piezoelectric coefficient d15 of c-axis oriented epitaxial Pb(Zr,Ti)O3 films

Piezoelectric shear strain was measured for c-axis oriented epitaxial Pb(Zr,Ti)O₃ (PZT) thin films. The PZT films, with a composition near the morphotropic phase boundary (MPB), were epitaxially grown on (001)MgO substrates and then microfabricated into a rectangular shape. Lateral electrodes were deposited on both sides of the PZT films to apply an external electric field perpendicular to the polarization. A sinusoidal input voltage of 100 kHz was applied between the lateral electrodes and in-plane shear vibration was measured by a laser Doppler vibrometer. In-plane displacement due to shear mode piezoelectric mode vibration was clearly observed and increased proportionally with the voltage. Finite element method (FEM) analysis was conducted to determine the horizontal electric field in the PZT film, and the piezoelectric coefficient d₁₅ was calculated to be 440×10^-12m/V.