abstract
High-performance Ba(Ti0.8Zr0.2)O-3-(Ba0.7Ca0.3)TiO3 (BCZT) fiber crystals were grown using laser-heated pedestal growth (LHPG) for a systematic investigation of processing effects on structure and physical properties. By changing the growth rate (200-5 mm/h), fiber crystals with varying stoichiometry were realized: controlled composition, Ba0.872Ca0.128Ti0.925Zr0.075O3-delta, for the optimized crystal (5 mm/h), relative to the ceramic sample (SS) synthesized by the ceramic method. SS and optimized fibers exhibited larger energy storage densities of 700 and 868 mJ/cm(3), respectively. Electrocaloric (EC) measurements by direct and indirect methods yielded Delta T of 1.3 K & 0.95 K and EC responsivity (Delta T/Delta E) of 0.3 and 0.43 K mm/kV for SS and 5 mm/h respectively, at 30 kV/cm, at least two-folds higher compared to 200 mm/h fiber. The EC responsivity of our samples is comparable to that of Pb(Mg,Nb)O-3 crystals. These results demonstrate that BCZT has potential application as EC elements when the composition is controlled by fine-tuning of growth parameters.
keywords
NANOCRYSTALLINE BATIO3; CRYSTAL-STRUCTURE; PHASE-TRANSITION; CERAMICS; RAMAN; PERFORMANCE; STRAIN; GROWTH
subject category
Materials Science, Ceramics
authors
Ramana, EV; Ferreira, NM; Mahajan, A; Tobaldi, DM; Bdikin, I; Rozic, B; Kutnjak, Z; Valente, MA
our authors
David Maria Tobaldi
Researcheracknowledgements
This work was developed within the scope of the project 032-88ARH/2018 (EVR) financed by national funds (OE) through the Portuguese foundation for science and technology (FCT), in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Authors also acknowledge financial support by I3N, UIDB/50025/2020 & UIDP/50025/2020 funded by FCT/MEC. IB wishes to acknowledge FCT for financial support: IF/00582/2015. BR and ZK gratefully acknowledge the financial support of Slovenian Research Agency programP1-0125 and the European Union Horizon 2020 Research and Innovation actions MSCA-RISE-ENGIMA (No. 778072).