Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 91: [MA] Poster II
O 91.27: Poster
Friday, March 30, 2012, 11:00–14:00, Poster A
Method to separate the anomalous Hall signal of different Co/Pt nanodots — •Carsten Thönnißen1, Alexander Neumann1, Simon Heße1, Andreas Meyer2, and Hans Peter Oepen1 — 1Institut für Angewandte Physik, Universität Hamburg, Germany — 2Institut für Physikalische Chemie, Universität Hamburg, Germany
On nanosized Hall crosses (<100nm) made via electron beam lithography (EBL) nanodots are created, which can be magnetically investigated with single dot sensitivity via anomalous Hall effect (AHE). The nanodots were fabricated from thin Co/Pt films using SiO2 particles as shadow mask for Ar+ ion milling at 150eV [1]. Due to the fact that the number of nanodots in the sensitive area of the cross varies between one and five it is necessary to separate the signals of the different nanodots. For that purpose we use a measurement setup similar to the van der Pauw method. The DC current is sent through adjoining legs of the Hall cross and a voltage drop is measured across the other legs. The obtained signal is proportional to the current through the dot and depends on the local current direction at the position of the dot. By cyclic permutation we obtain different signal ratios which allow us to identify the individual particles. By means of micrographs taken by scanning electron microscopy we identify the position and arrangement of the dots, which is used to simulate the voltage that has to be expected for the different geometries.
[1] H. Stillrich et al. Adv. Funct. Mat. 18, p76-81, (2008).