Giant Barocaloric Effect at the Spin Crossover Transition of a Molecular Crystal

Steven P. Vallone, Anthony N. Tantillo, Antonio M. dos Santos, Jamie J. Molaison, Rafal Kulmaczewski, Antonin Chapoy, Pezhman Ahmadi, Malcolm A. Halcrow, Karl G. Sandeman

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59 Citations (Scopus)
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The first experimental evidence for a giant, conventional barocaloric effect (BCE) associated with a pressure‐driven spin crossover transition near room temperature is provided. Magnetometry, neutron scattering, and calorimetry are used to explore the pressure dependence of the SCO phase transition in polycrystalline samples of protonated and partially deuterated [FeL2][BF4]2 [L = 2,6‐di(pyrazol‐1‐yl)pyridine] at applied pressures of up to 120 MPa (1200 bar). The data indicate that, for a pressure change of only 0–300 bar (0–30 MPa), an adiabatic temperature change of 3 K is observed at 262 K or 257 K in the protonated and deuterated materials, respectively. This BCE is equivalent to the magnetocaloric effect (MCE) observed in gadolinium in a magnetic field change of 0–1 Tesla. The work confirms recent predictions that giant, conventional BCEs will be found in a wide range of SCO compounds.
Original languageEnglish
Article number1807334
JournalAdvanced Materials
Issue number23
Early online date15 Apr 2019
Publication statusPublished - 6 Jun 2019


  • barocaloric effect
  • deuteration
  • solid-state cooling
  • spin crossover

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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