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Complete Set of Elastic Moduli of a Spin-Crossover Solid: Spin-State Dependence and Mechanical Actuation

Mikolasek, Mirko, Manrique-Juarez, Maria D., Shepherd, H.J., Ridier, Karl, Rat, Sylvain, Shalabaeva, Victoria, Bas, Alin-Ciprian, Collings, Ines, Chumakov, Aleksandr, Leichle, Thierry, and others. (2018) Complete Set of Elastic Moduli of a Spin-Crossover Solid: Spin-State Dependence and Mechanical Actuation. Journal of the American Chemical Society, 140 (28). pp. 8970-8979. ISSN 0002-7863. E-ISSN 1520-5126. (doi:10.1021/jacs.8b05347)

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Molecular spin crossover complexes are promising candidates for mechanical actuation purposes. The relationships between their crystal structure and mechanical properties remain, however, not well understood. In this study, combining high pressure synchrotron Xray diffraction and nuclear inelastic scattering measurements, we assessed the effective macroscopic bulk modulus (11.5 ± 2.0 GPa), Young’s modulus (10.9 ± 1.0 GPa) and Poisson’s ratio (0.34 ± 0.04) of the spin crossover complex [FeII(HB(tz)3)2] (tz = 1,2,4-triazol-1-yl) in its low spin state. Crystal structure analysis revealed a pronounced anisotropy of the lattice compressibility, which was correlated with the difference in spacing between the molecules in different crystallographic directions. Switching the molecules from the low spin to the high spin state leads to a remarkable drop of the Young’s modulus to 7.1 ± 0.5 GPa, which was also assessed in thin film samples by means of micromechanical measurements. These results are in agreement with the high cooperativity of the spin crossover in this compound and highlight its application potential in terms of recoverable stress (21 ± 1 MPa) and work density (15 ± 6 mJ/cm3).

Item Type: Article
DOI/Identification number: 10.1021/jacs.8b05347
Uncontrolled keywords: elastic properties, spin crossover, crystal structure, cooperativity, actuators
Subjects: Q Science > QC Physics
Q Science > QD Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Helena Shepherd
Date Deposited: 18 Jun 2018 14:23 UTC
Last Modified: 12 Jul 2019 10:13 UTC
Resource URI: (The current URI for this page, for reference purposes)
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