The ability to control electron spin degrees of freedom at the nanoscale is one of the crucial challenges in nanoscience both from fundamental and technological points of view. The scope of this talk is to show the capability of density-functional based methods to reproduce the properties of magnetic molecules in the gas phase, and to investigate the mechanisms through which magnetic coupling of a molecular spin with magnetic substrates can be achieved. More specifically, we have analyzed the magnetic coupling in heterometallic supramolecular dimers, i.e.purple-Cr7M/pyr/green-Cr7M’, by systematic variations of the M, M’magnetic ions, M, M’= Ni, Zn and Mn, and discussed the results in terms of the different exchange paths through the pyridine (pyr) linker. We have also addressed the case of a cobaltocene molecule adsorbed on graphene/ferromagnetic metal surfaces (e.g. Ni(111), and Fe or Co monolayers on Ni(111)), emphasizing the role of graphene in electronically decoupling the molecule from the metal substrates [1], while, on the other hand, allowing and mediating the exchange coupling between the molecular spin and the ferromagnetic layers below. Depending on the periodicity of the system (zero-dimensional for isolated molecules or three-dimensional for molecules on surface) under interest, codes employing localized gaussian (NWChem) or plane waves (VASP) basis set were used, respectively.
[1] S. Marocchi, P. Ferriani, NM Caffrey, F. Manghi, S. Heinze, V.Bellini, Physical Review B 88, 144407 (2013).
