Relaxor behavior and electrothermal properties of Sn- and Nb-modified (Ba,Ca)TiO3 Pb-free ferroelectric

Sarangi Venkateshwarlu, Sanjib Nayak, Frederick P. Marlton, Florian Weyland, Nikola Novak, Deepam Maurya, Yashaswini Veerabhadraiah, Olaf Borkiewicz, Kevin A. Beyer, Mads R.V. Jorgensen, Abhijit Pramanick*

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperReviewResearchpeer-review

12 Citations (Scopus)
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Abstract

Relaxor ferroelectrics have drawn attention for possible applications in solid-state cooling and thermal energy harvesting, owing to their electrothermal energy conversion properties. Here, we have synthesized and characterized the structure-property correlations of a new Sn- and Nb-doped (Ba,Ca)TiO3 relaxor ferroelectric with large pyroelectric and electrocaloric effects over a broad temperature range. We observed two peaks for the temperature-dependent pyroelectric coefficient: (i) -(∂P/∂T) ∼ 563 μC/(m2 K) at T∼ 270 K and (ii) -(∂P/∂T) ∼ 1021 μC/(m2 K) at T∼ 320 K. In addition, a broad peak for electrocaloric temperature change is observed near 320 K with a relative cooling power of ∼17 J/kg. These properties could be correlated to structural changes observed using X-ray diffraction at two different temperature ranges in the material. Analysis of high-energy X-ray scattering and specific heat capacity data revealed a transition from the cubic to tetragonal phase near Tm∼ 320 K, whereas an additional increase in the tetragonality (c/a) of the polar phase is observed below Ts∼ 270 K.

Original languageEnglish
JournalJournal of Materials Research
Volume35
Issue8
Pages (from-to)1017-1027
ISSN0884-2914
DOIs
Publication statusPublished - Apr 2020

Keywords

  • electrical properties
  • ferroelectric
  • X-ray diffraction

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