Тип публикации: статья из журнала
Год издания: 2024
Идентификатор DOI: 10.1088/1361-6463/ad211b
Аннотация: <jats:title>Abstract</jats:title> <jats:p>Double fluoride salts (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>M<jats:sup>4+</jats:sup>F<jats:sub>7</jats:sub> (M<jats:sup>4+</jats:sup>: Sn, Ti, Ge, Si) demonstrate a high efficiency of using chemical pressure as a tool for control and tuning structural ordering/disordering, sensitiПоказать полностьюvity to hydrostatic pressure, successions of the phase transitions, etc and, as a result, for purposeful variation within a wide range of parameters of barocaloric effect (BCE). The conventional and inverse BCEs near the triple points were found on the <jats:italic>T</jats:italic> − <jats:italic>p</jats:italic> phase diagrams, combination of which can be used to construct original cooling cycle in narrow temperature and pressure ranges. Reconstructive transformation between two cubic phases, <jats:inline-formula> <jats:tex-math><?CDATA $Pm ar{3}m \leftrightarrow Pa ar{3}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>P</mml:mi> <mml:mi>m</mml:mi> <mml:mover> <mml:mn>3</mml:mn> <mml:mo>ˉ</mml:mo> </mml:mover> <mml:mi>m</mml:mi> <mml:mo stretchy="false">↔</mml:mo> <mml:mi>P</mml:mi> <mml:mi>a</mml:mi> <mml:mover> <mml:mn>3</mml:mn> <mml:mo>ˉ</mml:mo> </mml:mover> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dad211bieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, realized in (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>SnF<jats:sub>7</jats:sub> at atmospheric pressure and in (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>TiF<jats:sub>7</jats:sub> at <jats:inline-formula> <jats:tex-math><?CDATA $p\gt$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>p</mml:mi> <mml:mo>></mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dad211bieqn2.gif" xlink:type="simple" /> </jats:inline-formula> 0.4 GPa are characterized by rather low thermal hysteresis, <jats:inline-formula> <jats:tex-math><?CDATA $\delta T_0$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>δ</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mn>0</mml:mn> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dad211bieqn3.gif" xlink:type="simple" /> </jats:inline-formula> = 1 K, and a great entropy change, <jats:inline-formula> <jats:tex-math><?CDATA $\Delta S_ extrm{BCE}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>S</mml:mi> <mml:mrow> <mml:mtext>BCE</mml:mtext> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dad211bieqn4.gif" xlink:type="simple" /> </jats:inline-formula> = 110–152 J (kg · K)<jats:sup>−1</jats:sup>, depending on the size of the central atom. At above 300–350 K, a contribution to BCE associated with the regular thermal expansion of the crystal lattice becomes comparable to entropy and temperature changes under pressure in the region of the phase transitions. An analysis of the absolute, relative and integral barocaloric characteristics of (NH<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>M<jats:sup>4+</jats:sup>F<jats:sub>7</jats:sub> compounds showed their high competitiveness with respect to other barocaloric materials considered as promising solid-state refrigerants.</jats:p>
Журнал: Journal of Physics D: Applied Physics
Выпуск журнала: Т. 57, № 17
Номера страниц: 175301
ISSN журнала: 00223727
Издатель: Institute of Physics and IOP Publishing Limited