Densification and enhanced polarisation in lead zirconate titanate sol–gel thin films

Isopressing a PbZr 0.3 Ti 0.7 O 3 sol–gel coating prior to thermally induced crystallisation leads to increased remanent polarisation ( P r ) values for optimum compaction pressures of ∼125 MPa. The value of P r increases from 25 μC cm −2 for a single layer 0.3 μm porous film prepared in the normal manner, to 34 μC cm −2 for an equivalent 0.2 μm dense film. Compaction pressures >135 MPa lead to little further increase in film density, but P r decreases to values below those of non-pressed porous samples. The trends in polarisation are attributed to the balance between the beneficial effects of decreased porosity and the detrimental effects of increased strain levels in the films.