Magnetoresistance of granular superconducting metals in a strong magnetic field
Abstract
The magnetoresistance of a granular superconductor in a strong magnetic field is considered. It is assumed that this field destroys the superconducting gap in each grain, such that all interesting effects considered in the paper are due to superconducting fluctuations. The conductance of the system is assumed to be large, which allows us to neglect all localization effects as well as the Coulomb interaction. It is shown that at low temperatures the superconducting fluctuations reduce the oneparticle density of states but do not contribute to transport. As a result, the resistivity of the normal state exceeds the classical resistivity approaching the latter only in the limit of extremely strong magnetic fields, and this leads to a negative magnetoresistance. We present detailed calculations of physical quantities relevant for describing the effect and make a comparison with existing experiments.
 Publication:

Physical Review B
 Pub Date:
 April 2000
 DOI:
 10.1103/PhysRevB.61.9145
 arXiv:
 arXiv:condmat/9910027
 Bibcode:
 2000PhRvB..61.9145B
 Keywords:

 74.80.Bj;
 74.40.+k;
 73.23.b;
 72.15.Rn;
 Fluctuations;
 Electronic transport in mesoscopic systems;
 Localization effects;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Superconductivity
 EPrint:
 24 pages, 10 figures