Accession Number:

AD0431920

Title:

NUCLEAR MAGNETIC RESONANCE IN SUPERCONDUCTING VANADIUM FILMS,

Descriptive Note:

Corporate Author:

CALIFORNIA UNIV BERKELEY

Personal Author(s):

Report Date:

1963-06-01

Pagination or Media Count:

78.0

Abstract:

Thin film NMR samples have been made of superconducting vanadium in pressures of less than 10 to the -6th power mm Hg, with thicknesses of 500, 200, and 100 A. After marked aging effects, these had normal state NMR linewidths typical of bulk V and superconducting linewidths consistent with calculated superconducting field exclusion. The transition temperatures were, respectively, 4.5, 3.6, and 2.8 K a large fraction of the films in the 100 A sample did not superconduct. The spin lattice relaxation rate 1T1 in the fully superconducting 200 A sample was proportional to the temperature to within 20 in both normal and superconducting states, and less than 4 change was seen in the metal NMR shift from normal to superconducting state at 0.4 Tc. Results on the 100 A sample were consistent with these. A discussion of susceptibility and nuclear shielding in metals shows that the formerly neglected orbital contribution is important in vanadium it is estimated that the lack of any change in superconducting metal shift implies less than 9 change in that part of the total susceptibility due to the ordinary Pauli spin susceptibility. The behavior of T1 is attributed to the lack of an energy gap in these samples. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE