Giant Barocaloric Effect at the Spin Crossover Transition of a Molecular Crystal |
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Authors: | Steven P Vallone Anthony N Tantillo Antnio M dos Santos Jamie J Molaison Rafal Kulmaczewski Antonin Chapoy Pezhman Ahmadi Malcolm A Halcrow Karl G Sandeman |
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Affiliation: | Steven P. Vallone,Anthony N. Tantillo,António M. dos Santos,Jamie J. Molaison,Rafal Kulmaczewski,Antonin Chapoy,Pezhman Ahmadi,Malcolm A. Halcrow,Karl G. Sandeman |
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Abstract: | 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. |
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Keywords: | barocaloric effect deuteration solid‐state cooling spin crossover |
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