On the processing conditions and interfacial chemistry of composite PZT thick films on platinised silicon substrates

Planar piezoelectric actuators have been fabricated in a range of complex geometries with PZT thick films on Platinised silicon. Spiral actuators have been fabricated where the spiral shape allows long beams to be contained compactly in order to aid deflection. The stabilisation of PZT thick films derived from composite slurries derived from powder sol dispersions has been achieved with a YSZ barrier layer. Interfacial formation of PtxPb intermetallic and PbSiO3 at the substrate electrode interface occurs at low and high oxygen partial pressures respectively. Densification of the thick film material, assisted by infiltration of sol, lowers interfacial po2 through inhibiting oxygen diffusion. Under extreme circumstances, re-oxidation of the intermetallic is not possible and it remains even after sintering. Densification of thick film materials proceeds more readily under an atmosphere of high oxygen partial pressure although in the absence of a suitable barrier layer, film delamination is promoted. Delamination was found to occur at the interface between electrode and substrate and not between film and electrode

Special Libraries, April 1933

Volume 24, Issue 3https://scholarworks.sjsu.edu/sla_sl_1933/1002/thumbnail.jp

Low temperature sol gel synthesis of PST thin films

Pb(Sc0.5Ta0.5)O3 (PST) thin films have been prepared by a Sol-Gel method to investigate the synthesis of the perovskite phase at low temperature. The effects of the composition of PST (amount of Pb excess) and the firing conditions (especially rapid thermal firing) have been studied. As a result of the experiments, it was found that rapid heating is effective for the synthesis of the perovskite phase and it is possible to deposit films at about 520°C. The Pb content of the sol does not have a marked effect upon the perovskite phase formation temperature, but it effectively depresses the formation of the intermediate pyrochlore phase

Low temperature formation of sol-gel derived ferroelectric lead zirconate titanate (Pb(ZrxTi1-x)O3, x = 0.3) thin films

Crack-free transparent thin films of ferroelectric Pb(Zr0.3, Ti0.7)O3 (PZT) with the perovskite structure were prepared by spin-coating a solution of complex alkoxides, followed by drying and then firing at the temperatures less than 500°C. The preparation of stock solution, drymg, and firing of films are described. The coatings with selective orientations have been prepared by using selective processing parameters. The influence of low-temperature processing steps on texture development will be reported. The formation and growth of polymeric particles in the hydrolysis and condensation of PZT sol-gel precursor solutions have been investigated by using photon correlation spectroscopy (PCS), small angle x-ray scattering (SAXS) and by measuring their rheological properties. It has been possible to follow the growth of the particles in the sol by the different techniques used from initial values of <4nm up to ca 100nm. It has been shown that the particles are rods rather than spheres. The effects of particle shape and solution chemistry on the crystal phase formation and texture development will be discussed

Influence of charged walls and defects on DC resistivity and dielectric relaxations in Cu-Cl boracite

Charged domain walls form spontaneously in Cu-Cl boracite on cooling through the phase transition. These walls exhibit changed conductivity compared to the bulk and motion consistent with the existence of negative capacitance. Here, we present the dielectric permittivity and DC resistivity of bulk Cu-Cl boracite as a function of temperature (-140 {\deg}C to 150 {\deg}C) and frequency (1 mHz to 10 MHz). The thermal behaviour of the two observed dielectric relaxations and the DC resistivity is discussed. We propose that the relaxations can be explained by the existence of point defects, most likely local complexes created by a change of valence of Cu and accompanying oxygen vacancies. In addition, the sudden change in resistivity seen at the phase transition suggests that conductive domain walls contribute significantly to the conductivity in the ferroelectric phase.Comment: 9 pages, 4 figure