Exploitation of magnetic bistability of molecules in spintronic devices requires that the molecules are connected to conducting substrates or electrodes. Transferring these peculiar single-molecule properties from the crystalline phase to the device is however far from trivial. Evidences of success in this process are still scarce. One relatively fortunate example is the family of Fe4 complexes that led to the first observation of Single-Molecule Magnet behaviour in a self-assembled monolayer, later extended also to thermally evaporable Fe4 clusters. The possibility to manipulate these molecules in UHV conditions allows an accurate control down to submonolayer coverages. A low temperature STM investigation has revealed a layer by layer growth of the film with the molecules adopting short-range hexagonal order and preferential orientation on the surface. Organization in a strict 2D lattice can significantly influence the quantum dynamics of the magnetization of SMM by enhancing the local dipolar fields and by altering the e evolution of the dipolar fields distribution during the relaxation process. Deposition on surfaces can also influence other degrees of freedom, stabilizing for instance different redox states, as recently detected by X-ray photoemission spectroscopy in a self-assembled monolayer of functionalized TbPc2 molecules on a silicon surface. SMMs are not the only bistable systems of interest for spintronic applications. Indeed Spin Crossover materials have been the target of an intense research focused at their switchable behavior when deposited on surface. Alternative switchable systems are those exhibiting an externally induced interconversion between redox isomers, also termed Valence Tautomerism, as in the case of cobalt complexes with dioxolene ligands. An overview of the research activity carried in the recently-established surface-science facilities flanking the Laboratory of Molecular Magnetism in Florence will be provided.

Bistability of magnetic molecules on surfaces: An overview

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.