Ferroelectric and Piezoelectric properties of (111) oriented lanthanum modified lead zirconate titanate film

• PLZT (111) film is prepared by spin coating of chemical sol on Pt (111) template.
• Piezoelectric d33 value (380 pm/V) of PLZT film is found 20% higher than PZT.
• Transverse piezocoefficient e31,f of PLZT film is reported for the first time.

Lanthanum modified lead zirconate titanate (PLZT) thick film with molecular formula of Pb0.92La0.08(Zr0.52Ti0.48)0.98O3 was grown preferentially along (111) direction on Pt/SiO2/Si (platinum/silicon oxide/silicon) substrate by spin coating of chemical solution. The directional growth of the film was facilitated by platinum (Pt) (111) template and rapid thermal annealing. X-ray diffraction pattern and atomic force microscopy revealed the preferential growth of the PLZT film. The film was characterized for ferroelectric and detailed piezoelectric properties in a parallel plate capacitor (metal–PLZT–metal) configuration. Ferroelectric characterization of the film showed saturated hysteresis loop with remanent polarization and coercive electric field values of 10.14 μC/cm2 and 42 kV/cm, respectively, at an applied field of 300 kV/cm. Longitudinal piezoelectric coefficient (d33,f) was measured by employing converse piezoelectric effect where electrical charge response and displacement were measured with electrical voltage excitation on the sample electrodes. The effective transverse piezoelectric coefficient (e31,f) was derived from charge measurement with an applied mechanical excitation strain by using the four point bending method. d33,f and e31,f coefficients of PLZT films were found to be 380 pm/V and − 0.831 C/m2 respectively.