Jp. Rodriguez, DECOUPLING OF LAYERED SUPERCONDUCTING FILMS IN PARALLEL MAGNETIC-FIELD, Journal of physics. Condensed matter, 9(24), 1997, pp. 5117-5135
The issue of the decoupling of extreme type-IT superconducting thin fi
lms (lambda(L)-->infinity) with weakly Josephson-coupled layers in mag
netic held parallel to the layers is considered via the corresponding
frustrated XY model used to describe the mixed phase in the critical r
egime. For the general case of arbitrary field orientations such that
the perpendicular magnetic field component is larger than the decoupli
ng crossover scale characteristic of layered superconductors, we obtai
n independent parallel and perpendicular vortex lattices. Specializing
to the double-layer case, we compute the parallel lower-critical fiel
d with entropic effects included, and find that it vanishes exponentia
lly as the temperature approaches the layer decoupling transition in z
ero field. The parallel reversible magnetization is also calculated in
this case, where we find that it shows a crossover phenomenon as a fu
nction of parallel field in the intermediate regime of the mixed phase
in lieu of a true layer-decoupling transition. It is argued that such
is the case for any finite number of layers, since the isolated doubl
e layer represents the weakest link.