Microstructural model on the evolution of domain structure during processing of PbTiO3 thin films on MgO(100) substrates

Abstract

A two-dimensional microstructural model is proposed to explain the origin of the 90 degrees domain structure of epitaxial PbTiO3 thin films grown on MgO(100) substrates by radio frequency sputter deposition, During film deposition at or above 600 degrees C, the film grows epitaxially in a cubic phase without any domain structure, At or just below the Curie temperature, the film mainly consists of a-domains with a small portion of c-domains nucleated in a triangular shape, The c-domains gradually expand with decreasing temperature to relax the strain energy caused by the difference in thermal contraction rate between the c-axis of a-domains and the substrate, forming consequently thin strips of a-domains distributed in the matrix of c-domains at room temperature.