Jp. Rodriguez, CRITICAL-BEHAVIOR OF THE FLUX-LINE TENSION IN EXTREME TYPE-II SUPERCONDUCTORS, Physical review. B, Condensed matter, 54(1), 1996, pp. 497-501
The entropic corrections to the flux-line energy of extreme type-II su
perconductors are computed using a schematic dual Villain model descri
ption of the flux quanta. We find that the temperature profile of the
lower critical field vanishes polynomially at the transition with an e
xponent nu congruent to 2/3 in the isotropic case, while it exhibits a
n inflection point for the case of weakly coupled layers in parallel m
agnetic field. It is argued that vestiges of these effects have alread
y been observed in high-temperature superconductors.