Piezoelectric response of pulsed laser deposited heterostructures PZT/YBCO, PLZT/YBCO

Thin films of lead zirconate titanate (PZT) and La doped lead zirconate tit anate (PLZT), coupled to layers of YBa2Cu3O7 (YBCO), were formed by pulsed laser deposition on MgO(100) substrates. Interferometric studies of piezoel ectric response of the heterostructures were performed with respect to DC e lectrical bias and AC measurement frequency. The piezoelectric coefficient demonstrated a hysteresis, consistent with polarization switching and relat ed to residual stress in PZT and PLZT films. A strong increase in the value s of piezoelectric coefficient d(33) from 15...30 pm/V up to 200...250 pm/V was found in both PZT and PLZT films with decrease in the measurement freq uency from 1 kHz to 60 Hz.