Combined contributions of phase structure and preferred orientation on the piezoelectric properties of polycrystalline (Pb0.94La0.04) Zr0.6Ti0.4O3 thin films

•Strain-induced monoclinic phase is evidenced in polycrystalline PLZT thin films.•Monoclinic phase and preferred orientation are favorable to films׳ piezoelectricity.

Polycrystalline (Pb0.94La0.04) Zr0.6Ti0.4O3 thin films were fabricated by a sol–gel method on the Pt (111)/Ti/SiO2/Si (100) substrates. Results from X-ray diffraction reveal that a strain-induced low-asymmetry monoclinic (MB) phase exists in all the films as compared with its powder counterpart. Also, films exhibit a simple trend of pyrolysis-sensitive (100)-orient growth. Good piezoelectric longitudinal coefficient values are obtained in the films where a maximum around 130 pm/V is reached for the film pyrolyzing at 425 °C. These findings suggest that combined contributions of monoclinic phase and (100)-preferred orientation type as well as good surface quality will account for excellent piezoelectric properties for ferroelectric films.

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