Stress induced shift of the Curie point in epitaxial PbTiO3 thin films

A 50 °C shift in Curie temperature has been observed for c-axis oriented PbTiO3 thin films using x-ray diffraction. An analysis of the electrostrictive strain based on the Devonshire thermodynamic formalism showed that the shift in the Curie point for these films can be plausibly explained by an effective two-dimensional compressive stress of ≊400 MPa. The single-domain, single-crystal dielectric susceptibility (η33) and piezoelectric coefficient (d33) were calculated and found to be relatively unaffected, at room temperature, by a compressive stress of this magnitude.