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Abstract: Fibre-textured and epitaxial Nb-doped Pb(Zr0.53Ti0.47)O3 (PNZT) thin films were grown on the different substrates by a sol–gel process. The [100]- and [111]-fibre-textured polycrystalline PNZT films were obtained on platinized silicon substrates by introducing PbO and TiO2 seeding layers, while the [001]- and [111]-oriented epitaxial PNZT films were formed directly on Nb-doped SrTiO3 (Nb:STO) single-crystal substrates with (100) and (111) surfaces, respectively. The preferential orientation and phase structure of the fibre-textured and epitaxial PNZT films, as well as their influences on the electrical properties were investigated. Higher remnant polarization (P r) and piezoelectric coefficient (d 33) were obtained for the epitaxial PNZT films on Nb:STO substrates than that for the fibre-textured ones on platinized silicon substrates. For both fibre-textured and epitaxial cases, the PNZT films with [100]/[001] orientations show higher piezoelectric responses than [111]-oriented ones, whereas better ferroelectric properties can be obtained in the latter. The intrinsic and extrinsic contributions were discussed to explain the difference in electrical properties for differently oriented fibre-textured and epitaxial PNZT films on different substrates. [Copyright &y& Elsevier]

Abstract: A shift of the morphotropic phase boundary (MPB) and a superior piezoelectric response are observed in Nb-doped Pb(Zr x Ti1− x )O3 (PNZT) thin films epitaxially grown on Nb-doped SrTiO3(100) (Nb:STO) substrates. X-ray diffraction and Raman spectra characterizations confirm that a phase transition from a tetragonal structure to a rhombohedral structure occurs when the Zr/Ti ratio varies from 20/80 to 80/20. The phenomenological theory and experimental analyses suggest that the MPB of epitaxial PNZT thin films is shifted to the higher Zr/Ti ratio (around 70/30) from the conventional ratio (52/48) due to the misfit compressive stress induced by the substrate. A maximum local effective longitudinal piezoelectric coefficient (d 33) up to 307pmV−1 is observed at a Zr/Ti ratio of 70/30 in the current compositional range, again confirming the shifting of MPB in epitaxial PNZT thin films. These findings offer a new insight for the fabrication of epitaxial PZT thin films at MPB with a superior piezoelectric response. [Copyright &y& Elsevier]

Epitaxial Pb(Zr,Ti)O3 (PZT) films were deposited on Nb-doped SrTiO3 (Nb:STO) monocrystalline wafers by a sol-gel method. It was observed that phase structure of prepared films depends on the orientation of Nb:STO substrates. Interestingly, tetragonal structure was only found for [001]-oriented PZT film on Nb:STO(100) substrate, whereas Nb:STO(111) substrate resulted in a [111]-oriented rhombohedral PZT film, regardless of Zr/Ti ratios ranging from 40/60 to 60/40. The influence of substrate orientation on phase structure of epitaxial PZT films was discussed on basis of the lattice matching. Ferroelectric and piezoelectric properties of PZT films on different Nb:STO substrates were also studied. [ABSTRACT FROM AUTHOR]

High-performance epitaxial niobium-doped lead zirconate titanate thin films [Pb(ZrxTi1-x)0.98Nb0.02O3] with a fixed thickness were deposited on [111]-cut single-crystalline SrTiO3 substrates by a sol-gel process as a function of Zr/Ti ratio ranging from 20/80 to 80/20. An obvious shift of morphotropic phase boundary (MPB) was observed in the [111]-oriented epitaxial films. Deviating from the Zr/Ti ratio of 52/48 in bulk materials, the MPB composition in the as-deposited films was found to move to a lower Zr/Ti ratio between 30/70 and 40/60, which agrees with the theoretical analysis on the basis of lattice mismatch between films and substrates and is further confirmed by the XRD patterns and Raman spectrum as well as ferroelectric test. Furthermore, a superior remnant polarization (Pr) value among all the compositions was obtained at a Zr/Ti ratio of 30/70, indicating that the extrinsic ferroelectric polarization near the new morphotropic phase boundary will lead to outstanding dielectric and piezoelectric performance in the epitaxial PZT thin film system. [ABSTRACT FROM AUTHOR]