Broad Phase Transition of Fluorite‐Structured Ferroelectrics for Large Electrocaloric Effect. Issue 9 (20th May 2019) - Park, Min Hyuk
Abstract : Field‐induced ferroelectricity in (doped) hafnia and zirconia has attracted increasing interest in energy‐related applications, including energy harvesting and solid‐state cooling. It shows a larger isothermal entropy change in a much wider temperature range compared with those of other promising candidates. The field‐induced phase transition occurs in an extremely wide temperature range, which contributes to the giant electrocaloric effect. This article examines the possible origins of a large isothermal entropy change, which can be related to the extremely broad phase transitions in fluorite‐structured ferroelectrics. While the materials possess a high entropy change associated with the polar–nonpolar phase transition, which can contribute to the high energy performance, the higher breakdown field compared with perovskites practically determines the available temperature range. Abstract : The theoretical origin of a large isothermal entropy change and the extremely broad phase transitions in fluorite‐structured ferroelectrics is examined. Fluorite‐structured ferroelectrics show a larger isothermal entropy change originating from field‐induced phase transitions in a much wider temperature range compared with those of other promising candidates due to intrinsically broad phase transitions.