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- Title
Comparative study of phase structure, dielectric properties and electrocaloric effect in novel high-entropy ceramics.
- Authors
Liu, Wei; Li, Feng; Chen, Guohua; Li, Guohui; Shi, Hongwei; Li, Li; Guo, Youmin; Zhai, Jiwei; Wang, Chunchang
- Abstract
Unique structure and performance in prominent high-entropy ceramics (HECs) have attracted enormous attentions recently. In this work, we have successfully synthesized pure-phase (Bi1/6Na1/6Sr1/6Ba1/6Pb1/6Ca1/6)TiO3 (BNSBPC) and (Bi1/6La1/6Na1/6K1/6Sr1/6Ba1/6)TiO3 (BLNKSB) HECs by conventional solid-state method. Rietveld refinement results show that BNSBPC composition possesses tetragonal phase (P4mm) while the BLNKSB one exhibits cubic phase (Pm 3 ¯ m). Dielectric characterization reveals distinct relaxation behaviors between BNSBPC and BLNKSB compositions. Relaxor-like nature in BNSBPC and Debye medium in BLNKSB one are verified by dielectric, ferroelectric and Raman spectra characterizations. Maximal electrocaloric effect (ECE, ΔTmax) reaches 0.63 K with relatively narrow temperature span (ΔTspan) of ~ 20 K at 60 kV cm−1 for BNSBPC ceramic, while the BLNKSB one possesses superior temperature stability (ΔTspan = 100 K) with ΔTmax = 0.14 K. Room-temperature ECE is also obtained by home-made adiabatic calorimeter, which indicates a positive ECE for both compositions. Finally, phase structure, dielectric properties and ECE in two high-entropy compositions are comparatively discussed to explore structure–ECE relationships in HECs. The superior thermal stability of ECE in BLNKSB samples provides a broad prospect for designing solid-state refrigeration.
- Subjects
PYROELECTRICITY; DIELECTRIC properties; RIETVELD refinement; RAMAN spectroscopy; COMPARATIVE studies; THERMAL stability; CERAMICS
- Publication
Journal of Materials Science, 2021, Vol 56, Issue 33, p18417
- ISSN
0022-2461
- Publication type
Article
- DOI
10.1007/s10853-021-06530-9