10.1021/acsnano.6b04107.s001 Simone Marocchi Simone Marocchi Andrea Candini Andrea Candini David Klar David Klar Willem Van den Heuvel Willem Van den Heuvel Haibei Huang Haibei Huang Filippo Troiani Filippo Troiani Valdis Corradini Valdis Corradini Roberto Biagi Roberto Biagi Valentina De Renzi Valentina De Renzi Svetlana Klyatskaya Svetlana Klyatskaya Kurt Kummer Kurt Kummer Nicholas B. Brookes Nicholas B. Brookes Mario Ruben Mario Ruben Heiko Wende Heiko Wende Umberto del Pennino Umberto del Pennino Alessandro Soncini Alessandro Soncini Marco Affronte Marco Affronte Valerio Bellini Valerio Bellini Relay-Like Exchange Mechanism through a Spin Radical between TbPc<sub>2</sub> Molecules and Graphene/Ni(111) Substrates American Chemical Society 2016 Ni presence calculation experiment Relay-Like Exchange Mechanism XMCD Tb ion DFT relay-like communication pathway TbPc 2 Molecules graphene decoupling layer interaction substrate Pc ligands mediates 2016-10-11 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Relay-Like_Exchange_Mechanism_through_a_Spin_Radical_between_TbPc_sub_2_sub_Molecules_and_Graphene_Ni_111_Substrates/4029333 We investigate the electronic and magnetic properties of TbPc<sub>2</sub> single ion magnets adsorbed on a graphene/Ni(111) substrate, by density functional theory (DFT), <i>ab initio</i> complete active space self-consistent field calculations, and X-ray magnetic circular dichroism (XMCD) experiments. Despite the presence of the graphene decoupling layer, a sizable antiferromagnetic coupling between Tb and Ni is observed in the XMCD experiments. The molecule–surface interaction is rationalized by the DFT analysis and is found to follow a relay-like communication pathway, where the radical spin on the organic Pc ligands mediates the interaction between Tb ion and Ni substrate spins. A model Hamiltonian which explicitly takes into account the presence of the spin radical is then developed, and the different magnetic interactions at play are assessed by first-principle calculations and by comparing the calculated magnetization curves with XMCD data. The relay-like mechanism is at the heart of the process through which the spin information contained in the Tb ion is sensed and exploited in carbon-based molecular spintronics devices.