Measurement of piezoelectric coefficients of lead zirconate titanate thin films by strain-monitoring pneumatic loading method

A method to simultaneously measure the longitudinal (d₃₃) and transverse (d₃₁) piezoelectric coefficients of a lead zirconate titanate (PZT) thin film was developed. This system was based on the pneumatic loading method but was modified to monitor the radial strain when a pressurized gas was introduced into the chamber. The results of the bulk piezoelectric material measured by this system coincided with that measured by both the Berlincourt method and the resonance method. The effective d₃₃ and the real d₃₁ of the PZT thin film fabricated by the sol-gel multiple coating method, and poled at 300kV/cm were 125 and -60pC/N, respectively. The real d₃₃ estimated upon considering the constraints by the silicon substrate was 180pC/N.