Low-electric-field-induced high electrocaloric properties via defect regulation in samarium-doped BaTiO3 ceramics
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...
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Veröffentlicht in: | Journal of alloys and compounds 2024-06, Vol.989, p.174362, Article 174362 |
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Sprache: | eng |
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Zusammenfassung: | 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.
•Enhanced ECE is achieved via introducing defect dipoles/polarization into BT-based ceramics.•Different charge compensation states and defect structures are shown by changing Sm3+ doped content.•High polarization change consisting of spontaneous & defect polarization change contributes to the high ECE.•High ΔT of ∼1.11 K and large ΔT/ΔE of ∼0.037 K·cm kV−1 are obtained under a low electric field. |
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ISSN: | 0925-8388 1873-4669 |
DOI: | 10.1016/j.jallcom.2024.174362 |