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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.4: Poster
Donnerstag, 29. März 2007, 14:00–17:45, Poster A
Low Temperature Magnetoresistance Measurements on Bismuth Nanowire Arrays — •Christoph Kaiser1,2, Georg Weiss1, Thomas Cornelius3, Maria Eugenia Toimil-Molares3, and Reinhard Neumann3 — 1Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe — 2New address: Institut für Mikro- und Nanoelektronische Systeme, Universität Karlsruhe, D-76187 Karlsruhe — 3Gesellschaft für Schwerionenforschung, D-64291 Darmstadt
We created nanoporous templates by exposing polymeric foils to heavy ion radiation. In these templates, single-crystalline bismuth nanowires were fabricated by electrochemical deposition. The resistance and magnetoresistance of these nanowires were studied at low temperatures. We present our results and compare them with the common theories and results of other groups, respectively.
We obeserved an unexpected effect in the low temperature resistance of our nanowires when a magnetic field was present. This novel effect could be related to the temperature dependence of the magnetoresistance. Furthermore, a clear B1.5 dependence of the transverse magnetoresistance was found. The expected T2 dependence of the resistance at low temperatures is confirmed in the temperature range 1.5 K < T <10 K. Finally, a steplike increase in the magnetoresistance of our sample with a wire diameter of 100 nm was found, extending the results of Heremans et al. to larger diameters. This effect is attributed to a transition from one- to three-dimensional localization.