Electrocaloric effect in BaTiO${}_3$: a first-principles-based study on the effect of misfit strain

Abstract

We address the question of how the electrocaloric effect in epitaxial thin films of the prototypical ferroelectric BaTiO${}_3$ is affected by the clamping to the substrate and by substrate-induced misfit strain. We use molecular dynamics simulations and a first-principles-based effective Hamiltonian to calculate the adiabatic temperature change $\Delta T$ under different epitaxial constraints. Our results demonstrate that, consistent with phenomenological theory, clamping by the substrate reduces the maximum $\Delta T$ compared to bulk BaTiO${}_3$. On the other hand, compressive misfit-strain leads to a strong increase of $\Delta T$ and shifts the maximum of the electrocaloric effect to higher temperatures. A rather small compressive strain of $-0.75$% is sufficient to obtain a $\Delta T$ that is larger than the corresponding bulk value.

References in corpus (2)

• Giant electrocaloric effect around T${}_c$
• First-principles accurate total-energy surfaces for polar structural distortions of BaTiO3, PbTiO3, and SrTiO3: consequences to structural transition temperatures

Cited by in corpus (1)

• Tuning the caloric response of BaTiO${}_3$ by tensile epitaxial strain