Energy storage, electrocaloric and optical property studies in Ho-modified NBT – BT lead-free ferroelectric ceramics

Sekhar, K.S.K.R. Chandra and Sreenivasu, T. and Babu, K. Vijaya and Asthana, Saket and et al, . (2022) Energy storage, electrocaloric and optical property studies in Ho-modified NBT – BT lead-free ferroelectric ceramics. Ceramics International. pp. 1-12. ISSN 0272-8842

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Abstract

A comprehensive investigation of structural, microstructural, optical, electrocaloric, and energy storage properties of Ho-modified NBT-BT lead-free ceramics was conducted from room temperature to a high-temperature region. Rietveld refinement confirms the coexistence of dual-phase monoclinic (Cc) and tetragonal (P4mm) phases in Ho-modified NBT-BT ceramics. A prominent monoclinic distortion was found with increasing Ho composition up to x=0.02, and then an abrupt decrease for x=0.03 ceramic was noticed. Of particular importance is the composition of x = 0.02, which exhibits a high electrocaloric temperature change (ΔT) of 0.73 K @ E = 20 kV/cm at a temperature of 373 K, and an optimal high recoverable energy storage density (Wrec) of 1.8846 J/cm3 along with an efficiency 83% was achieved. The frequency dependence ac-conductivity study promotes the reduction of oxygen vacancies at room temperature and the dominance of single ionized oxygen vacancies at very high temperatures well above 300 °C. A small considerable increase in the energy bandgap values with the Ho3+ ion substitution in NBT-BT was observed. Under the excitation of 532 nm light, the two most prominent red fluorescence emission peaks were emitted, where the first emission band with weak intensity was observed at 657 nm which corresponds to the 5F5 → 5I8 transition, and a strong 2nd peak at 756 nm corresponds to the 5F4/5S2 →5I7 level transition of the Ho3+ ion. These findings provide a feasible multifunctional property in the applications of power electronic devices with lead-free NBT-BT ceramics via rare-earth substitution. © 2022

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IITH Creators:	IITH Creators ORCiD Asthana, Saket http://orcid.org/0000-0002-6420-3304
Item Type:	Article
Additional Information:	The author TP would like to thank UGC – DAE , BARC – India, for ( UDCSR/MUM/CD/CRSM-261/2017 ) project funded under the collaborator research scheme.
Uncontrolled Keywords:	Adiabatic temperature change; Antiferroelectric; Energy storage density; Lead-free; Na0.5Bi0.5TiO3
Subjects:	Physics
Divisions:	Department of Physics
Depositing User:	. LibTrainee 2021
Date Deposited:	23 Nov 2022 11:06
Last Modified:	23 Nov 2022 11:06
URI:	http://raiithold.iith.ac.in/id/eprint/11368
Publisher URL:	https://doi.org/10.1016/j.ceramint.2022.10.363
OA policy:	https://v2.sherpa.ac.uk/id/publication/13167
Related URLs:	Author Google Scholar

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