Investigation of superconducting inhomogeneities in Nb and Nb3Sn by penetration depth measurements Δlambda(T,f,Bsub(ac))
Description
Measurements are reported of the superconducting penetration depth Δlambda(T,f,Bsub(ac)) on Nb and Nb3Sn in the low frequency region (10 kHz <= f <= 350 kHz). For niobium, Δlambda shows deviations from the BCS-behavior of homogenious superconductors: Δlambda shows a step around 7 K and a BCS-like behavior above 8 K, which yields too short mean free paths l. As we will show, these deviations can be explained by oxygen-rich regions going normal around 7 K. A simple model using the proximity effect is worked out, describing the results consistently and yielding mean free paths which are in agreement with other surface measurements. Penetration depth measurements have been used for optimizing the preparation technique of Nb3Sn layers on Nb resulting in very homogenious Nb3Sn layers. (orig./GSCH)
Availability note (English)
MF available from INIS under the Report Number.Abstract (German)
Es wird ueber Eindringtiefenmessungen Δlambda(T,f,Bsub(ac)) an Nb und Nb3Sn im Niederfrequenzbereich (10 kHz <= f <= 350 kHz) berichtet. Δlambda von Niob zeigt Abweichungen vom BCS-Verlauf homogener Materialien: eine Stufe in Δlambda bei etwa 7 K und fuer T > 8 K einen BCS-aehnlichen Verlauf, der jedoch zu kurze freie Weglangen l liefert. Die Abweichungen ruehren von sauerstoffreichen Gebieten her, die bei etwa 7 K normalleitend werden. Mit Hilfe eines einfachen Proximity-Effekt-Modells koennen die Messergebnisse konsistent beschrieben und freie Weglaengen bestimmt werden, die mit anderen Oberflaechenmessungen uebereinstimmen. Mit Eindringtiefenmessungen konnte das Praeparationsverfahren fuer Nb3Sn-Schichten optimiert und die bisher homogensten Nb3Sn-Schichten hergestellt werden. (orig./GSCH)
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Additional details
Additional titles
- Original title (German)
- Untersuchung von supraleitenden Inhomogenitaeten in Nb und Nb
Publishing Information
- Imprint Pagination
- 68 p.
- Report number
- KFK-EXT--3/76-4
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 7269883
- Subject category
- S71: CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- INTERMETALLIC COMPOUNDS; MAGNETIC FIELDS; MEISSNER-OCHSENFELD EFFECT; NIOBIUM; NIOBIUM ALLOYS; PROXIMITY EFFECT; ROUGHNESS; SUPERCONDUCTORS; SURFACE TREATMENTS; TIN ALLOYS; TRANSITION TEMPERATURE
- Descriptors DEC
- ALLOYS; ELEMENTS; METALS; PHYSICAL PROPERTIES; SURFACE PROPERTIES; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT ALLOYS; TRANSITION ELEMENTS
Optional Information
- Notes
- 59 refs.; with figs.