Preferred orientation of solution derived (Pb,Ca)TiO3 thin films on SrTiO3 and MgO

Calcium modified lead titanate thin films have been prepared by spin-coating sol-gel process. Several layers of 0.3 M precursor solution containing a 10 mol% excess of PbO were deposited on (100)SrTiO₃ and (100)MgO, previously platinized by rf-magnetron sputtering with a 100 mm Pt layer. Each solution layer was directly crystallized by a rapid heating at 700°C. X-ray diffraction analysis (XRD) of the films shows the growth of the (Pb,Ca)TiO₃ perovskite. A strong degree of [001] orientation is measured for the perovskite films on both substrates. Pyroelectricity of the films have been measured using a dynamic method. Pyroelectric coefficients result from the order obtained for poled ceramics of the same composition. Correlation between the [001] enhanced orientation and the spontaneous polarization is discussed based on pyroelectric and dielectric constant measurements