Advertisement

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
Ceramics
  • 112 Downloads

Abstract

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.

Notes

Acknowledgements

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.

References

  1. 1.
    Leblanc M, Maisonneuve V, Tressaud A (2015) Crystal chemistry and selected physical properties of inorganic fluorides and oxide-fluorides. Chem Rev 115:1191–1254CrossRefGoogle Scholar
  2. 2.
    Mazej Z, Hagiwara R (2007) Hexafluoro-, heptafluoro-, and octafluoro-salts, and \([\text{ M }_{{\rm n}}\text{ F }_{5{{\rm n}}+1}]^{-}\) (\(\text{ n }=2, 3, 4\)) polyfluorometallates of singly charged metal cations, \(\text{ Li }^{+}\), \(\text{ Cs }^{+}\), \(\text{ Cu }^{+}\), \(\text{ Ag }^{+}\), \(\text{ In }^{+}\) and \(\text{ Tl }^{+}\). J Fluor Chem 128:423–437CrossRefGoogle Scholar
  3. 3.
    Laptash NM, Udovenko AA, Emelina TB (2011) Dynamic orientation disorder in rubidium fluorotantalate. Synchronous Ta-O and Ta-F vibrations. J Fluor Chem 132:1152–1158CrossRefGoogle Scholar
  4. 4.
    Agulyansky A (2003) Potassium fluorotantalate in solid, dissolved and molten conditions. J Fluor Chem 123:155–161CrossRefGoogle Scholar
  5. 5.
    Pogorel’tsev E, Mel’nikova S, Kartashev A, Gorev M, Flerov I, Laptash N (2017) Thermal, optical, and dielectric properties of fluoride \(\text{ Rb }_{2}\text{ TaF }_{7}\). Phys Solid State 59:986–991CrossRefGoogle Scholar
  6. 6.
    Pogorel’tsev EI, Mel’nikova SV, Kartashev AV, Molokeev MS, Gorev MV, Flerov IN, Laptash NM (2013) Ferroelastic phase transitions in \((\text{ NH }_{4})_{2}\text{ TaF }_{7}\). Phys Solid State 55:611–618CrossRefGoogle Scholar
  7. 7.
    Mel’nikova SV, Bogdanov EV, Molokeev MS, Laptash NM, Flerov IN (2019) Optical and calorimetric studies of \(\text{ K }_{2}\text{ TaF }_{7}\). J Fluor Chem 222–223:75–80CrossRefGoogle Scholar
  8. 8.
    Boča M, Rakhmatullin A, Mlynáriková J, Hadzimová E, Vasková Z, Mičušík M (2016) Differences in XPS and solid state NMR spectral data and thermo-chemical properties of iso-structural compounds in the series \(\text{ KTaF }_{6}\), \(\text{ K }_{2}\text{ TaF }_{7}\) and \(\text{ K }_{3}\text{ TaF }_{8}\) and \(\text{ KNbF }_{6}\), \(\text{ K }_{2}\text{ NbF }_{7}\) and \(\text{ K }_{3}\text{ NbF }_{8}\). Dalton Trans 44:17106–17117Google Scholar
  9. 9.
    Langer V, Smrčok L, Boča M (2006) Dipotassium heptafluorotantalate(V), \(\beta \)-\(\text{ K }_{2}\text{ TaF }_{7}\), at 509 K. Acta Cryst E 62:i91–i93CrossRefGoogle Scholar
  10. 10.
    Torardi C, Brixner L, Blasse G (1987) Structure and luminescence of \(\text{ K }_{2}\text{ TaF }_{7}\) and \(\text{ K }_{2}\text{ NbF }_{7}\). J Solid State Chem 67:21–25CrossRefGoogle Scholar
  11. 11.
    Kartashev AV, Flerov IN, Volkov NV, Sablina KA (2008) Adiabatic calorimetric study of the intense magnetocaloric effect and the heat capacity of \((\text{ La }_{0.4}\text{ Eu }_{0.6})_{0.7}\text{ Pb }_{0.3}\text{ MnO }_3\). Phys Solid State 50:2115–2120CrossRefGoogle Scholar
  12. 12.
    Gorev M, Bogdanov E, Flerov I (2017) T-p phase diagrams and the barocaloric effect in materials with successive phase transitions. J Phys D Appl Phys 50:384002CrossRefGoogle Scholar
  13. 13.
    Gorev M, Bogdanov E, Flerov I (2017) Conventional and inverse barocaloric effects around triple points in ferroelastics \((\text{ NH }_{4})_{3}\text{ NbOF }_{6}\) and \((\text{ NH }_{4})_{3}\text{ TiOF }_{5}\). Scr Mater 139:53–57CrossRefGoogle Scholar
  14. 14.
    Gorev MV, Flerov IN, Bogdanov EV, Voronov VN, Laptash NM (2010) Barocaloric effect near the structural phase transition in the \(\text{ Rb }_{2}\text{ KTiOF }_{5}\) oxyfluoride. Phys Solid State 52:377–383CrossRefGoogle Scholar
  15. 15.
    Pogorel’tsev E, Flerov I, Kartashev A, Bogdanov E, Laptash N (2014) Heat capacity, entropy, dielectric properties and T-p phase diagram of \((\text{ NH }_{4})_{3}\text{ TiF }_{7}\). J Fluor Chem 168:247–250CrossRefGoogle Scholar
  16. 16.
    Flerov IN, Kartashev AV, Gorev MV, Bogdanov EV, Mel’nikova SV, Molokeev MS, Pogorel’tsev EI, Laptash NM (2016) Thermal, structural, optical, dielectric and barocaloric properties at ferroelastic phase transition in trigonal \((\text{ NH }_{4})_{2}\text{ SnF }_{6}\): A new look at the old compound. J Fluor Chem 183:1–9CrossRefGoogle Scholar
  17. 17.
    Lloveras P, Stern-Taulats E, Barrio M, Tamarit JL, Crossley S, Li W, Pomjakushin V, Planes A, Mañosa L, Mathur ND, Moya X (2015) Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate. Nat Commun 6:8801CrossRefGoogle Scholar
  18. 18.
    Mañosa L, González-Alonso D, Planes A, Bonnot E, Barrio M, Tamarit JL, Aksoy S, Acet M (2010) Giant solid-state barocaloric effect in the Ni-Mn-In magnetic shape-memory alloy. Nat Mater 9:478–481CrossRefGoogle Scholar
  19. 19.
    Mañosa L, González-Alonso D, Planes A, Barrio M, Tamarit JL, Titov IS, Acet M, Bhattacharyya A, Majumdar S (2011) Inverse barocaloric effect in the giant magnetocaloric La-Fe-Si-Co compound. Nat Commun 2:595CrossRefGoogle Scholar
  20. 20.
    Yuce S, Barrio M, Emre B, Stern-Taulats E, Planes A, Tamarit JL, Mudryk Y, Gschneidner KA, Pecharsky VK, Mañosa L (2012) Barocaloric effect in the magnetocaloric prototype \(\text{ Gd }_{5}\text{ Si }_{2}\text{ Ge }_{2}\). Appl Phys Lett 101:071906CrossRefGoogle Scholar

Copyright information

© 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

Personalised recommendations