Magnetic slow relaxation in a Metal Organic Framework made of chains of ferromagnetically coupled Single-Molecule Magnets.

Abstract

We report the study of a Dy-based metal-organic framework (MOF), with unprecedented magnetic properties. The compound is made of nine-coordinated DyIII magnetic building blocks (MBBs) with poor intrinsic single-molecule magnet behaviour. 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 behaviour 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 magnet and single molecule magnet that host intra-chain couplings that cancel quantum tunneling between the MBBs. This compound evidences that bottom-up approach via MOF design can induce spontaneous organization of MBBs able to produce remarkable molecular magnetic material.