Magnetic Slow Relaxation in a Metal-Organic Framework Made of Chains of Ferromagnetically Coupled Single-Molecule Magnets

Gang Huang (1) , Guglielmo Fernandez-Garcia (1, 2) , Insa Badiane (1, 3) , Magatte Camarra (1, 3) , Stéphane Freslon (1) , Olivier Guillou (1) , Carole Daiguebonne (1) , Federico Totti (2) , Olivier Cador (1) , Thierry Guizouarn (1) , Boris Le Guennic (1) , Kevin Bernot (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 UniFI - Università degli Studi di Firenze = University of Florence
3 LCPM - Groupe Matériaux Inorganiques:Chimie Douce et Cristallographie

We report the study of a Dy-based metal-organic framework (MOF) with unprecedented magnetic properties. The compound is made of nine-coordinated Dy-III magnetic building blocks (MBBs) with poor intrinsic single-molecule magnet behavior. However, the MOF architecture constrains the MBBs in a one-dimensional structure that induces a ferromagnetic coupling between them. Overall, the material shows a magnetic slow relaxation in absence of external static field and a hysteretic behavior at 0.5K. Low-temperature magnetic studies, diamagnetic doping, and ab initio calculations highlight the crucial role played by the Dy-Dy ferromagnetic interaction. Overall, we report an original magnetic object at the frontier between single-chain magnets and single-molecule magnets that host intrachain couplings that cancel quantum tunneling between the MBBs. This compound is evidence that a bottom-up approach through MOF design can induce spontaneous organization of MBBs able to produce remarkable molecular magnetic materials.

Keywords: single-molecule magnets; single-chain magnets; lanthanides; metal-organic frameworks; ferromagnetic coupling

Domains: Chemical Sciences; Coordination chemistry; Chemical Sciences; Material chemistry

Gang Huang, Guglielmo Fernandez-Garcia, Insa Badiane, Magatte Camarra, Stéphane Freslon, et al.. Magnetic Slow Relaxation in a Metal-Organic Framework Made of Chains of Ferromagnetically Coupled Single-Molecule Magnets. Chemistry - A European Journal, 2018, 24 (27), pp.6983-6991. ⟨10.1002/chem.201800095⟩. ⟨hal-01807090⟩