Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 42: Superconductivity: Fabrication, Properties, Electronic Structure
TT 42.2: Vortrag
Donnerstag, 29. März 2012, 15:15–15:30, H 3005
Low-temperature transport in ultra-thin tungsten films — •Olivio Chiatti1,2, Christopher Nash2, and Paul Warburton2 — 1Neue Materialien, Institut f. Physik, Humboldt-Univ. zu Berlin, D-10099 Berlin — 2London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WC1H 0AH, UK
Tungsten-containing films, fabricated by focused-ion-beam-induced chemical vapour deposition, are known to have an enhanced superconducting transition temperature compared to bulk tungsten [1], and have been investigated previously for film thickness down to 25 nm [2]. In this work, by using ion-beam doses below 50 pC/µm2 on a substrate of amorphous silicon, we have grown continuous films with thickness below 20 nm. The electron transport properties were investigated at temperatures down to 350 mK and in magnetic fields up to 3 T, parallel and perpendicular to the films. The films in this work are closer to the limit of two-dimensional systems and are superconducting at low temperatures. Magnetoresistance measurements yield upper critical fields of the order of 1 T, and the resulting coherence length is smaller than the film thickness.
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