Séminaire en visioconférence.
Laurent Limot - DR CNRS à l’Université de Strasbourg, CNRS, IPCMS (UMR 7504)
Abstract
Recent advances in scanning probe techniques rely on the chemical functionalization of the probe-tip termination with single molecules weakly connected to the metallic apex. Information, otherwise inaccessible with a metallic tip, can be gathered in this way. The success of this approach opens the prospect of introducing spin sensitivity through the probe-tip termination by a magnetic molecule. Here, we use a nickelocene-terminated tip (Nc-tip), which offers the possibility of producing spin excitations on the tip apex of a scanning tunneling microscope (STM). We show that when the Nc-tip is a hundred pm away from point contact with a surface-supported object, magnetic effects may be probed through changes in the spin excitation spectrum of nickelocene. We use this detection scheme to determine the exchange field and the spin polarization of the sample with atomic-scale resolution. Our findings demonstrate that the Nc-tip is a powerful probe for investigating surface magnetism with STM, from single magnetic atoms to surfaces