Pseudo-first-order phase transition for ultrahigh positive/negative electrocaloric effects in perovskite ferroelectrics

• Published in: Nano energy Vol. 16; pp. 419 - 427
• Main Authors: Wu, Hong-Hui, Zhu, Jiaming, Zhang, Tong-Yi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2015
• Subjects: Phase field simulations; Positive/negative electrocaloric effects; Pseudo-first-order phase transition; Solid-state cooling devices; Thermodynamics analysis; Positive/negative electrocaloric effects; Solid-state cooling devices; Phase field simulations; Pseudo-first-order phase transition; Thermodynamics analysis
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2015.06.030

The electrocaloric effect of ferroelectric materials, which occurs significantly near the first-order paraelectric/ferroelectric transition (FOPFT) Curie temperature, has tremendous prospect in solid-state cooling devices. In the present work, thermodynamics analysis and phase field simulations were conducted to demonstrate the mechanical compression-induced two types of pseudo-first-order phase transition, which could occur at a temperature below the Curie temperature. Thus, in one material there may coexist ultrahigh positive and negative electrocaloric effects, which are associated with the two pseudo-first-order phase transitions and tunable by the magnitude of the compression. The mechanical compression-induced pseudo-first-order phase transition and the coexistence of positive and negative electrocaloric effects will facilitate the development of a novel technology to design and manufacture next generation of solid-state cooling devices. Two types of pseudo-first-order phase transition (PFOPT) coexist in ferroelectric materials, which occur at temperatures lower than the paraelectric/ferroelectric transition Curie temperature. Ultrahigh positive and negative electrocaloric effects are associated with the PFOPTs which could fully utilized an applied electric field during its loading and unloading. [Display omitted] •Compression induced two types of pseudo-first-order phase transitions.•Drop/jump of macroscopic polarization along the direction of applied electric field.•Coexistence of positive and negative electrocaloric effects in a ferroelectrics.