Near‐Room‐Temperature Large Electrocaloric Effect in Barium Titanate Single Crystal Based on the Electric Field–Temperature Phase Diagram

Abstract

Phase transition plays a key role in the electrocaloric effect, but the first-order ferroelectric-paraelectric phase transition always occurs far above room temperature, which heavily limits the practical application. Herein, the focus is on the orthorhombic-tetragonal first-order ferroelectric-ferroelectric phase transition (@288 K) in <011>-oriented barium titanate single crystal. Ferroelectric properties under a high electric field indicate a reversible field-induced tetragonal-orthorhombic phase transition, based on which the electric fieldtemperature phase diagram is established. It is strongly related to the enhanced electrocaloric effect, and a large adiabatic temperature change of 1.33 K is obtained at 288 K under 15 kV cm À1 , that is, a high electrocaloric strength of 88.7 mK cm kV À1 . The large electrocaloric effect near room temperature makes lead-free BaTiO 3 a promising candidate for next-generation solid-state refrigeration.

Electrocaloric effect in BaTiO3 multilayer capacitors with first-order phase transitions

“…The corresponding latent heats for FE-to-FE and FE-to-PE phase transitions are 0.3 kJ kg −1 and 1 kJ kg −1, respectively. These values match previously reported data in BTO single crystals[27,28] and ceramics[29]. Interestingly, the latent heat of the FE-to-PE phase transition is almost equal to the latent heat reported in PST ceramics (1 kJ kg −1 ) or MLCCs (1.2 kJ kg −1 ), which display a large EC effect of 5.5 K[19,30].The phase transition temperatures deduced from the temperature-dependent dielectric constant curves in figure2(b) are in line with the values from DSC.…”

Correlation between multi-factor phase diagrams and complex electrocaloric behaviors in PNZST antiferroelectric ceramic system

“…As mentioned above, the J-E curve is an important tool to identify FE/AFE properties. The J peak reflects the domain switching or phase transition process, and the corresponding electric field is the critical electric field [41,42]. Based on the J-E curves at different temperatures, Fig.…”

Resilience of the Aurivillius structure upon La and Cr doping in a Bi5Ti3FeO15 multiferroic

“…45,46 The ferroelectric ground states of these compounds are highly sensitive to intercalation units which influence their electrocaloric, energy storage, and energy sensor applications. [47][48][49] In principle, the ferroelectric domain patterns are favorable to form polar nanoregions, which are driven by the gradient of elastic energy and dipole interactions. The nano-domain patterns are the source of the high energy storage behavior.…”