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Title: Landau theory and giant room-temperature barocaloric effect in M F 3 metal trifluorides

Abstract

The structural phase transitions of MF 3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF 6 octahedra associated with soft antiferrodistortive optic modes that are coupled to long-wavelength strain generating acoustic phonons. We calculate the temperature and pressure dependence of several quantities such as the spontaneous distortions, volume expansion, and shear strains as well as T - P phase diagrams. By contrasting our model to experiments we quantify the deviations from mean-field behavior and find that the tilt fluctuations of the MF 6 octahedra increase with metal cation size. We apply our model to predict giant barocaloric effects in Sc-substituted TiF 3 of up to about 15 JK -1 kg -1 for modest hydrostatic compressions of 0.2GPa. The effect extends over a wide temperature range of over 140K (including room temperature) due to a large predicted rate, dT c/dP = 723K GPa -1, which exceeds those of typical barocaloric materials. Our results suggest that open lattice frameworks such as the trifluorides are an attractive platform to search for giant barocaloric effects.

Authors:
 [1];  [2];  [3];  [4]
  1. Univ. of Costa Rica, San Jose (Costa Rica)
  2. Yale Univ., New Haven, CT (United States)
  3. Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Univ. of Costa Rica, San Jose (Costa Rica); Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1411962
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Materials; Journal Volume: 1; Journal Issue: 5
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Corrales-Salazar, A., Brierley, R. T., Littlewood, P. B., and Guzmán-Verri, G. G.. Landau theory and giant room-temperature barocaloric effect in MF3 metal trifluorides. United States: N. p., 2017. Web. doi:10.1103/PhysRevMaterials.1.053601.
Corrales-Salazar, A., Brierley, R. T., Littlewood, P. B., & Guzmán-Verri, G. G.. Landau theory and giant room-temperature barocaloric effect in MF3 metal trifluorides. United States. doi:10.1103/PhysRevMaterials.1.053601.
Corrales-Salazar, A., Brierley, R. T., Littlewood, P. B., and Guzmán-Verri, G. G.. 2017. "Landau theory and giant room-temperature barocaloric effect in MF3 metal trifluorides". United States. doi:10.1103/PhysRevMaterials.1.053601.
@article{osti_1411962,
title = {Landau theory and giant room-temperature barocaloric effect in MF3 metal trifluorides},
author = {Corrales-Salazar, A. and Brierley, R. T. and Littlewood, P. B. and Guzmán-Verri, G. G.},
abstractNote = {The structural phase transitions of MF3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF6 octahedra associated with soft antiferrodistortive optic modes that are coupled to long-wavelength strain generating acoustic phonons. We calculate the temperature and pressure dependence of several quantities such as the spontaneous distortions, volume expansion, and shear strains as well as T - P phase diagrams. By contrasting our model to experiments we quantify the deviations from mean-field behavior and find that the tilt fluctuations of the MF6 octahedra increase with metal cation size. We apply our model to predict giant barocaloric effects in Sc-substituted TiF3 of up to about 15 JK-1 kg-1 for modest hydrostatic compressions of 0.2GPa. The effect extends over a wide temperature range of over 140K (including room temperature) due to a large predicted rate, dTc/dP = 723K GPa-1, which exceeds those of typical barocaloric materials. Our results suggest that open lattice frameworks such as the trifluorides are an attractive platform to search for giant barocaloric effects.},
doi = {10.1103/PhysRevMaterials.1.053601},
journal = {Physical Review Materials},
number = 5,
volume = 1,
place = {United States},
year = 2017,
month =
}