THE GINZBURG-LANDAU EXPANSION AND THE SLOPE OF THE UPPER CRITICAL-FIELD IN DISORDERED SUPERCONDUCTORS

It is shown that the slope of the upper critical field \dH(c2)/dT\(Tc) in superconductors with d pairing drops rapidly with increasing conce ntration of normal impurities, while in superconductors with anisotrop ic s pairing \dH(c2)/dT\(Tc) increases and reaches the well-known asym ptotic level characteristic for the isotropic case. This difference ma kes it possible, in principle, to employ measurements of Hz in disorde red superconductors as an experimental method for determining the type of pairing in high-T-c superconductors and systems with heavy fermion s. (C) 1996 American Institute of Physics.