Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Surface Magnetism IV
MA 55.2: Vortrag
Donnerstag, 17. März 2011, 15:30–15:45, HSZ 103
Orientation-dependent Kondo resonance of the Ni2(hfaa)4(bpm) and Mn2(hfaa)4(bpm) single molecular magnets — •Lei Zhang1, Michael Schackert1, Toshio Miyamachi1, Toyokazu Yamada1, Frank Schramm2, Mario Ruben2, and Wulf Wulfhekel1 — 1Physikalisches Institut, Karlsruhe Institut of Technology, Germany — 2Institut of Nanotechnology, Karlsruhe Institut of Technology, Germany
Single molecular magnets (SMM) attract much interest due to their potential applications in spintronics. We investigated metal organic molecules based on (hfaa)4(bpm) containing two 3d ions (Ni or Mn) using low temperature scanning tunneling microscopy (STM) at 1 K in ultra-high vacuum. In the bulk, the two metallic ions couple antiferromagnetically leading to an S=0 ground state [1,2].
The Ni2 and Mn2 molecules were sublimed onto atomically clean Cu(100) surfaces resulting in two different absorptions configurations. Scanning tunneling spectroscopy (STS) with a high energy resolution of 0.3 meV showed a strong Kondo resonance on the position of the metal ions inside the molecules indicating that the hybridization of the local spins with the substrate is more efficient than their antiferromagnetic coupling. The Fano resonance showed a pronounced dependence on the adsorption geometry indicating different Kondo temperatures and q-parameters. This is explained by a adsorption dependent hybridization between SMM and the substrate.
[1] G. Brewer et al., Inorg. Chem. 24, 4580-4584 (1985)
[2] M. Barquín et al., Transition Metal Chemistry 24, 546-552 (1999)