Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 26: Superconductivity: Vortex Dynamics, Vortex Phases, Pinning

TT 26.3: Talk

Wednesday, February 27, 2008, 16:15–16:30, H 3010

Commensurability effects in Nb thin films with randomly diluted pinning arrays — •Daniel Bothner¹, Matthias Kemmler¹, Konstantin Ilin², Michael Siegel², Reinhold Kleiner¹, and Dieter Koelle¹ — ¹Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena, Universität Tübingen, Germany — ²IMS, Universität Karlsruhe, Germany

We study experimentally the critical depinning current I_c versus applied magnetic field B in Nb thin films, which contain 2D arrays of circular antidots arranged in randomly diluted triangular lattices.

For measurements of electric transport close to the Nb transition temperature T_c, the sample temperature is controlled and stabilized via an optical, very low noise heating system.

We investigate samples with fixed lattice constant as well as such with fixed antidot-density and compare dilutions between 0% and 80%. Our results show some interesting features in the I_c(B) patterns as commensurability effects at nonmatching fields and a significant suppression of vortex channeling for higher magnetic fields as predicted by Reichhardt et al. [1].

[1] C. Reichhardt and C.J. Olson Reichhardt, Phys. Rev. B 76, 094512(2007)