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TT: Tiefe Temperaturen

TT 20: Postersitzung IV (Mesoskopische Systeme, Supraleitung: Massivmaterialien, Bandleiter, Pinning, Vortexdynamik, Transporteigenschaften, Korngrenzen)

TT 20.3: Poster

Donnerstag, 27. März 2003, 14:30–19:00, P2c, P2d

Vortex Motion Noise in Microstructured Amorphous Nb_0.7Ge_0.7 Thin Films — •Dinko Babic^1,2, Johannes Bentner¹, Christoph Sürgers³, Wilfried Meindl¹, Franziska Rohlfing¹, Thomas Nussbaumer⁴, Christian Schönenberger⁴, and Christoph Strunk¹ — ¹Universität Regensburg, D-93040 Regensburg — ²Universität Zagreb, Kroatien — ³Universität Karlsruhe, D-76128 Karlsruhe — ⁴Universität Basel, Schweiz

The intrinsic pinning in amorphous Nb_0.7Ge_0.7 is very weak. This permits investigation of vortex motion shot noise in superconducting microbridges in a new regime. Shot noise of a measurable magnitude appears when vortices move by essentially individual hops from one pinning site to another. The extracted shot-noise slopes are close but not equal to the theoretical value 2φ₀. This leads to a conclusion that they are determined by the ratio of the hop length and sample width. Since amorphous Nb_0.7Ge_0.7 has an extended state of negligible intrinsic pinning, further work (in progress) exploits nanostructuring of the artificial pinning centres in order to tune the shot noise.