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Giant Barocaloric Effect at the Spin Crossover Transition of a Molecular Crystal
Author(s) -
Vallone Steven P.,
Tantillo Anthony N.,
dos Santos António M.,
Molaison Jamie J.,
Kulmaczewski Rafal,
Chapoy Antonin,
Ahmadi Pezhman,
Halcrow Malcolm A.,
Sandeman Karl G.
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201807334
Subject(s) - materials science , spin crossover , condensed matter physics , deuterium , neutron scattering , crystallite , calorimetry , bar (unit) , neutron diffraction , transition temperature , relaxation (psychology) , atmospheric temperature range , superconductivity , neutron , crystallography , thermodynamics , crystal structure , chemistry , nuclear physics , physics , metallurgy , meteorology , psychology , social psychology
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 [FeL 2 ][BF 4 ] 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.