Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 91: [MA] Poster II
O 91.43: Poster
Freitag, 30. März 2012, 11:00–14:00, Poster A
Quantitative MFM on superconducting thin films — •Henry Stopfel1, Silvia Vock1, Tetyana Shapoval1, Volker Neu1, Ulrike Wolff1, Dmytro S. Inosov2, Silvia Haindl1, Jan Engelmann1, Rudolf Schäfer1, Bernhard Holzapfel1, and Ludwig Schultz1 — 1IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, 01171 Dresden, Germany — 2Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
Quantitative interpretation of magnetic force microscopy (MFM) data is a challenge, because the measured signal is a convolution between the magnetization of the tip and the stray field emanated by the sample. It was established theoretically that the field distribution just above the surface of the superconductor can be well approximated by the stray field of a magnetic monopole [1]. The description of the MFM tip, however, needs a second approximation. The temperature-dependent vortex-distribution images on a NbN thin film were fitted using two different tip models. Firstly, the magnetic tip was assumed to be a monopole that leads to the simple monopole-monopole model for the tip-sample interaction force. Performing a 2D fitting of the data with this model, we extracted λ, Δ and the vortex pinning force [2]. Secondly, a geometrical model was applied to calculate the tip-transfer-function of the MFM tip using the numerical BEM method [3].
[1] G. Carneiro and E. H. Brandt, PRB 61, 6370 (2000)
Shapoval T. et al., PRB 83, 214517 (2011)
Vock S. et al., IEEE Transactions on Magnetics 47, 2352 (2011)