Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DS: Dünne Schichten

DS 22: Postersitzung

DS 22.25: Poster

Dienstag, 9. März 2004, 14:30–17:00, Poster B

Excess noise in current-biased ultra-thin superconducting nano-structures — •Alexei Semenov, Heiko Richter, Andreas Engel, and Heinz-Wilhelm Hübers — DLR Institute of Planetary Research

Noise properties of ultra-thin films deserve particular interest because they shine light on the dynamics of the superconducting phase transition and are of importance in metrology and detector technology. We have studied electrical noise appearing in nano-structured current-biased superconducting rectangular (length - l, width - w) bridges made from ultra-thin NbN films. For both wide (w > l) and narrow (w < l) bridges we have observed similar behaviour: at currents close to the critical current, the noise increased rapidly in excess to generation-recombination, shot or thermal fluctuation noise. The magnitude and temperature dependence of the excess noise evidences that this noise most likely originates from random formation of the phase-slip centres (PSC). The spectrum of the excess noise suggests the intrinsic lifetime of a PSC is of the order of the electron-phonon interaction time.