Switchable slow relaxation of magnetization in the native low temperature phase of a cooperative spin-crossover compound

Urtizberea, A. ; Roubeau, O. (Universidad de Zaragoza)

Resumen: The implementation of single-molecule magnet properties in spin crossover materials is sought as a unique source of magnetic multistability at the molecular level. Examples however remain extremely scarce, in part due to the diamagnetic state of most Fe(ii) spin crossover materials at low temperatures. We have studied the complex [Fe(mtz)6](CF3SO3)2 (mtz = 1-methyltetrazole) as a tantalizing candidate of such coexistence, due to its known partial spin crossover and therefore paramagnetic native low temperature phase. The single-crystal structures of [Fe(mtz)6](CF3SO3)2 reported here allow rationalizing its peculiar cooperative spin-crossover behavior. Importantly, the high-spin Fe crystallographic sites at low temperature exhibit a high symmetry with a local trigonal distortion, usually source of magnetic anisotropy. The analysis of equilibrium magnetic properties confirm the presence of a significant magnetic anisotropy at the Fe(ii) high spin sites in the high symmetry low temperature phase. This results in field-induced slow relaxation of their magnetization which is dominated at low temperature by tunneling and direct processes and is strongly enhanced above 3 K by Raman and Orbach processes. Unprecedentedly, these single-molecule magnet properties are observed in the native ground state of a spin crossover material and efficiently and reversibly switched OFF through visible light irradiation.

Idioma: Inglés

DOI: 10.1039/c6sc04737h

Año: 2017

Publicado en: CHEMICAL SCIENCE 8, 3 (2017), 2290-2295
ISSN: 2041-6520

Factor impacto JCR: 9.063 (2017)

Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 18 / 171 = 0.105 (2017) - Q1 - T1

Factor impacto SCIMAGO: 4.508 - Chemistry (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E98-MOLCHIP
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2014-53961-R
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2015-70868-ERC

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)