Journal of Materials Science

, Volume 54, Issue 23, pp 14287–14295 | Cite as

Heat capacity, thermal expansion and barocaloric effect in fluoride \(\hbox {K}_{2}\hbox {TaF}_{7}\)

  • I. N. FlerovEmail author
  • M. V. Gorev
  • A. V. Kartashev
  • E. I. Pogorel’tsev
  • N. M. Laptash


The heat capacity and thermal expansion of potassium heptafluorotantalate were studied. The room temperature phase \(P2_1/c\) is stable at least to 4 K. The strong first-order phase transition \(P2_1/c - Pnma\) at \(T_0=486.2\,\hbox {K}\) is accompanied by giant changes in the entropy, \(\Delta S_0=22.3\,\hbox {J}\,(\hbox {mol}\,\hbox {K})^{-1},\) and volume strain, \(\delta V_0/V=-\,3.6\%\). A rather high sensitivity of \(\hbox {K}_{2}\hbox {TaF}_{7}\) to pressure was found, \({\text {d}}T_0/{\text {d}}p=-\,220 \,\hbox {K}\,\hbox {G}\,\hbox {Pa}^{-1}\). Significant extensive and intensive barocaloric effects are found at low pressure. The possibility of improving the barocaloric properties is discussed.



The reported study was funded by RFBR according to the research Project No. 18-02-00269_a.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interest.


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Kirensky Institute of Physics, Federal Research Center KSC Siberian BranchRussian Academy of SciencesKrasnoyarskRussia
  2. 2.Institute of Engineering Physics and RadioelectronicsSiberian Federal UniversityKrasnoyarskRussia
  3. 3.Astafijev Krasnoyarsk State Pedagogical UniversityKrasnoyarskRussia
  4. 4.Institute of Chemistry, Far East BranchRussian Academy of SciencesVladivostokRussia

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