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Vortex motion noise in micrometer-sized thin films of the amorphous Nb0.7Ge0.3 weak-pinning superconductor

Babi, Dinko; Nussbaumer, Thomas; Strunk, Christoph; Schönenberger, Christian; Sürgers, Christoph

Abstract:
We report high-resolution measurements of voltage (V) noise in the mixed state of micrometer-sized thin films of amorphous Nb0.7Ge0.3, which is a good representative of weak-pinning superconductors. There is a remarkable difference between the noise below and above the irreversibility field Birr. Below Birr, in the presence of measurable pinning, the noise at small applied currents resembles shot noise, and in the regime of flux flow at larger currents decreases with increasing voltage due to a progressive ordering of the vortex motion. At magnetic fields B between Birr and the upper critical field Bc2 flux flow is present already at vanishingly small currents. In this regime the noise scales with (1-B/Bc2)2V2 and has a frequency (f) spectrum of 1/f type. We interpret this noise in terms of the properties of strongly driven depinned vortex systems at high vortex density.

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Originalveröffentlichung
DOI: 10.1103/PhysRevB.66.014537
Scopus
Zitationen: 9
Web of Science
Zitationen: 9
Dimensions
Zitationen: 7
Zugehörige Institution(en) am KIT Physikalisches Institut (PHI)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2002
Sprache Englisch
Identifikator ISSN: 1098-0121
KITopen-ID: 20552002
Erschienen in Physical review B
Verlag American Physical Society (APS)
Band 66
Heft 1
Seiten 014537-014540
Nachgewiesen in Dimensions
Web of Science
Scopus
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