Effect of stress state on the domain configuration and switching behavior in ferroelectric thin films

The effect of ferroelastic coupling in ferroelectric thin films under in-plane compressive and tensile stress states was investigated under the framework of the Landau–Ginzburg–Devonshire theory coupled with microscopic examinations and characterization measurements. Piezoresponse force microscopy imaging and synchrotron studies suggested the presence of increased c-domain population in PLZT films (Pb_0.92La_0.08Zr_0.52Ti_0.48O₃) under compressive stress than tensile stress. Stress-induced ferroelectric order (SFO) persisted in PLZT films at temperatures greater than the Curie temperature. The SFO was dependent on the magnitude of the stress, not the stress state, and PLZT films on nickel and silicon substrates exhibited stress-induced remanent polarization values of 8 μC cm⁻² and 4 μC cm⁻², respectively. Pre-stressing thin films using thermal expansion mismatch shows promise as a method to develop high-temperature piezoelectric devices and has advantages over inducing misfit strains.