Upper bounds on the electrocaloric effect in polar solids

Abstract

Physical upper bounds on the electrocaloric effect (ECE) in bulk polar solids are derived using thermodynamic and statistical mechanics arguments. It is shown that the maximum ECE temperature change ΔT under saturation can be estimated from the dielectric data, such as the saturation polarization and effective Curie constant, as well as from the orientational degeneracy Ω of the elementary dipolar entities in the system and the specific heat of the material. Also obtained is a universal relation for the theoretical maximum value of ΔT, which depends only on Ω and the molar specific heat.