Magnetic field dependence of the microwave surface resistance of pure niobium

Journal Article · Thu Jan 01 04:00:00 EST 1976 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00655219· OSTI ID:4057353

Segal, H. R.; McLean, W. L.

The microwave surface resistance of pure niobium was measured in magnetic fields up to H/sub c3/. The surface resistance in the mixed state was found to depend strongly on the mean free path, in contrast to the earlier theory of Caroli and Maki but in agreement with the recent theoretical work of Cerdeira, Houghton, and Maki. Estimates of the constant of proportionality in the mean- free-path dependence are limited in accuracy by the present uncertainty in the values of kappa$sub 2$(T). Agreement with the mean free path dependence predicted by the recent theory could not be achieved by incorporating measurements above H/sub c2/ into a simple layer model to adjust the measured values of the surface resistance with the steady field parallel to the surface. However, the discrepancy between the predicted and measured anisotropies was reduced by this procedure. Other aspects of the experimental results that fall outside the range of validity of the recent theory are compared with general features established by earlier experimental and theoretical work on impure type II superconductors. In particular, the anisotropy of the surface resistance in fields just below H/sub c3/ was found to be temperature independent, as predicted by Thompson and confirmed by Monceau and Waysand. The observed magnetic hysteresis effects in the mixed state are discussed in relation to the nascent vortex model and to the existence of an oxygen-rich surface layer.

• Research Organization: Rutgers-the State Univ., New Brunswick, NJ
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-023797
• OSTI ID: 4057353
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 1-2 Vol. 22; ISSN 0022-2291
• Publisher: Plenum Press
• Country of Publication: United States
• Language: English

Related Subjects

*NIOBIUM-- MAGNETORESISTANCE
360104* --Materials--Metals & Alloys--Physical Properties
ANISOTROPY
CRITICAL FIELD
MAGNETIC FIELDS
MEAN FREE PATH
N50230* --Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
N66200 --Physics (Low Temperature)--Superconductivity
ORIENTATION
SURFACES
TYPE-II SUPERCONDUCTORS