钐
材料科学
钛酸钡
电场
兴奋剂
陶瓷
偶极子
极化(电化学)
铁电陶瓷
电热效应
凝聚态物理
热电性
光电子学
复合材料
化学
电介质
铁电性
无机化学
物理
物理化学
量子力学
有机化学
作者
Haopeng Feng,Huajin Wen,Yanli Huang,Bo Wu,Wenjuan Wu,Xiao Wu,Min Gao,Tengfei Lin,Cong Lin,Chunlin Zhao
标识
DOI:10.1016/j.jallcom.2024.174362
摘要
A small electrocaloric effect (ECE) is usually observed in aliovalent doped ferroelectric ceramics since decreased polarization is usually present. In this work, the high ECE is achieved in a barium titanate [BaTiO3 (BT)]-based ceramic by introducing defect polarization to enhance the ferroelectric polarization and polarization change. The defect dipoles consisting of donor ion and barium vacancy, or barium and oxygen vacancies were formed in samarium-doped (Ba1−1.5xSmx)TiO3 ceramics. The phase and defect structures, and dielectric and ferroelectric properties are analyzed to confirm the evolution of charge compensation states and defect structures, and the influences of defects on polarization rotation and ECE. An enhanced ferroelectric polarization and high internal bias field are present in the ceramic with a suitable defect dipole effect, leading to a high polarization change before/after applying an electric field, causing an enhanced ECE. Finally, a high electrocaloric temperature change of ~1.11 K and a large electrocaloric strength of ~0.037 K·cm kV−1 were achieved under a low electric field of 30 kV/cm, indicating that forming suitable defect dipoles can optimize the ECE. This work provides a significant paradigm for tuning ECE in ferroelectric materials via defect regulation.
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