Influence of bending deformation in spherulitic films of lead zirconate titanate on the formation of the internal field and self-polarization

Experimental studies of the internal field and self-polarization in thin lead zirconate titanate films formed on platinized silicon substrates using a two-stage radio-frequency magnetron sputtering of a ceramic target were conducted. In the first stage, amorphous films were deposited on a cold substrate, and in the second stage, high-temperature annealing was performed, accompanied by crystallization of the perovskite phase and the formation of a spherulitic microstructure. The aging characteristics of these films, associated with the formation of non-uniform mechanical stresses leading to the upward diffusion of oxygen vacancies (the Gorsky effect), were studied. Estimates were made of the diffusion rate of oxygen vacancies, as well as their concentration, necessary for the formation of an internal field in thin films. It was shown that a change in the crystallization (synthesis) temperature of the perovskite phase can lead to a change in the direction of the gradient vector of non-uniform mechanical stresses and the direction of diffusion of oxygen vacancies towards the substrate.