Effect of misfit strain on the electrocaloric effect of polydomain epitaxial ferroelectric thin films

The effect of misfit strain on the electrocaloric effect in polydomain epitaxial BaTiO₃ thin films at room temperature is investigated using the Ginzburg-Landau-Devonshire thermodynamic theory. Numerical calculations indicate that the misfit strain has a large impact on the ferroelectric polarization states and the electrocaloric effect. Most importantly, the electrocaloric effect in the polydomain ca₁/ca₂/ca₁/ca₂ phase is much larger than that in the monodomain c phase and the other polydomain phases. Consequently, a large electrocaloric effect can be obtained by carefully controlling the misfit strain, which may provide potential applications in refrigeration devices.