Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.42: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Vortex dynamics in Nb films on faceted substrate surfaces — •Oleksiy K. Soroka1, Michael Huth2, Valerij A. Shklovskij3, Jens Oster1, and Hermann Adrian1 — 1Institute of Physics, Johannes Gutenberg-University, Staudinger Weg 7, D-55099 Mainz, Germany — 2Institute of Physics, Johann Wolfgang Goethe-University, Robert-Mayer-Str. 2-4, D-60054 Frankfurt, Germany — 3Kharkiv National University, Physical Department, 4 Svobody Sq., 61077 Kharkiv, Ukraine
Anisotropy of the viscous damping force in superconductor can lead to the existence of the preferred directions for the vortices to move. Such a guided vortex motion leads to the appearance of new components in the galvanomagnetic response of the sample: an additional odd longitudinal and even transversal magnetoresistive components with respect to magnetic field reversal.
Perfect vortex guiding alon the facet rigdes was proved in Nb-films on faceted α-Al2O3 by magnetoresistivity measurements. The thin film sample consisted of five microbridges oriented at the angles 0∘, 30∘, 45∘, 60∘ and 90∘ with respect to the facet ridges. Field inversion was used to separate the even and odd components of the magnetoresistivities to obtain the contributions caused by the guided vortex motion.
The temperature dependences of the even longitudinal magnetoresistivity of the samples could be well fitted within the theoretical approach proposed by V. A. Shklovskij, using for the isotropic and anisotropic pinning potential a simple potential with a symmetric triangular wells whose depths were estimated from the experimental data.