1. Giant Barocaloric Effect at the Spin Crossover Transition of a Molecular Crystal
- Author
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Antonio M. dos Santos, Antonin Chapoy, Pezhman Ahmadi, Jamie J. Molaison, Karl G. Sandeman, Steven P Vallone, Rafal Kulmaczewski, Anthony N Tantillo, and Malcolm A. Halcrow
- Subjects
Phase transition ,Materials science ,Mechanical Engineering ,Gadolinium ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Calorimetry ,Neutron scattering ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Crystal ,chemistry ,Mechanics of Materials ,Spin crossover ,Magnetic refrigeration ,General Materials Science ,0210 nano-technology ,Bar (unit) - 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.
- Published
- 2019
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