Influence of the electric field on the latent heat of the ferroelectric phase transition in KDP

TL;DR

This study investigates how electric fields influence the latent heat during the ferroelectric phase transition in KDP crystals, revealing that latent heat decreases with increasing electric field and vanishes at a critical field.

Contribution

It provides the first simultaneous measurements of specific heat, heat flux, and dielectric constant under electric fields to accurately evaluate latent heat in KDP.

Findings

Latent heat decreases as electric field increases.

Critical electric field where latent heat vanishes is approximately 0.44 kV/cm.

Dielectric permittivity measurements suggest latent heat relates to domain growth.

Abstract

The specific heat, heat flux (DTA trace) and dielectric constant of KDP ferroelectric crystal have been measured simultaneously for various electric fields with a conduction calorimeter. The specific heat presents a strong anomaly but these simultaneous measurements allow us to evaluate the latent heat accurately. Latent heat decreases with field and the value of critical electric field --that where latent heat disappears-- is estimated to be (0.44\pm0.03) kV/cm. Incidentally, we have measured simultaneously the dielectric permittivity which suggests that latent heat is developed as domains are growing.