Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 31: Surface Magnetism / Magnetic Imaging II

MA 31.10: Talk

Thursday, March 25, 2010, 17:45–18:00, H23

Spin-dependent quantum interference within a single Co nanoisland — •Hirofumi Oka, Sebastian Wedekind, Guillemin Rodary, Dirk Sander, Pavel Ignatiev, Larissa Niebergall, Valeri Stepanyuk, and Jürgen Kirschner — Max-Planck-Institute of Microstructure Physics, Weinberg 2, D-06120, Halle, Germany

We present a combined experimental and theoretical study of spin-polarized electron confinement on individual Co nanoislands on Cu(111). Low-temperature SP-STM in magnetic fields is used to identify parallel (P) and anti-parallel (AP) states of the magnetization orientation between a Co island and a magnetic tip.[1,2] We find a pronounced spatial modulation of the differential conductance (dI/dV) within one island, which is ascribed to electron confinement, in both states. Maps of the asymmetry of the dI/dV, (dI/dV_AP−dI/dV_P)/(dI/dV_AP+dI/dV_P), which is related to the spin-polarization within the Co islands, show strong spatial variations and bias-voltage dependence of the contrast. Comparing the results with theory, we conclude that the modulated spin-polarization and its variation with energy can be described by the relative magnitudes between majority and minority spin states, where the spatial modulation is mainly due to electron confinement of the majority state.

[1] G. Rodary et al., JJAP 47, 9013 (2008). [2] G. Rodary et al., APL 95, 152513 (2009).

*Present address (G.R.): Laboratoire de Photonique et Nanostructures, CNRS UPR20, 91460 Marcoussis, France