Orientation-engineered 0.5BaZr0.2Ti0.8O3-0.5Ba0.7Ca0.3TiO3 (BZT-BCT) thin films were deposited on La0.7Sr0.3MnO3-coated SrTiO3 single-crystalline (001), (110), and (111) substrates by off-axis radio-frequency magnetron sputtering. X-ray diffraction confirmed a highly epitaxial growth of all the as-deposited films. It is believed the strong orientation dependence of ferroelectric and piezoelectric properties on the films is attributed to the relative alignment of crystallites and spontaneous polarization vector. The optimal ferroelectric response lies in the [001] direction, whereas a comparatively large effective piezoelectric coefficient d33,eff of 100.1 ± 5 pm/V was attained in [111] BZT-BCT thin film, suggesting its potential application for high-performance lead-free piezoelectric devices.

Thickness dependence (over the range d=1.05 to 0.02 μm) of the coercive electric fields, Ec, of niobium-doped lead-zirconium-titanate (PNZT) films has been investigated in pulsed laser ablated c-axis-oriented PNZT/YBa2Cu3O7−x heterostructures deposited on LaAlO3 substrates. Our studies show that Ec has a d−2/3 dependence in good agreement with the domain nucleation model developed for ferroelectric single crystals by Kay and Dunn [Philos. Mag. 7, 2027 (1962)]. Reproducible structural properties as well as ferroelectric properties with rather high polarization which is independent of the film thickness have been obtained in these Nd:YAG pulsed laser ablated films.

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