Size-dependent Ultrahigh Electrocaloric Effect near Pseudo-First-Order Phase Transition Temperature in Barium Titanate Nanoparticles

Most ferroelectric materials, however, bear the second-order paraelectric/ferroelectric transition (SOPFT). In the present study, we demonstrate a size-dependent pseudo-first-order phase transition (PFOPT), associated with ultrahigh ECE and Curie temperature in ferroelectric nanoparticles with degradation layers by employing phase field modeling.

The PFOPT behavior of the polarization component P3 along the applied electric field direction x3 versus temperature is similar to the classical FOPFT behavior. The results indicate that the ultrahigh ECE and PFOPT occur at temperatures below the Curie temperature of a given nanoparticle size. The adiabatic temperature change is 3.347 K in the simulated barium titanate nanoparticle of 10 × 10 × 8 normalized size under a 96.502 kV cm−1 applied electric field change.