2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/24731We discuss the zero field superconducting phase transition in a finite system of magnetically coupled superconducting layers. Transverse screening is modified by the presence of other layers resulting in topological excitations with fractional flux. Vortex stacks trapping a full flux and present at any finite temperature undergo an evaporation transition which corresponds to the depairing of fractional-flux vortices in individual layers. We propose an experiment with a bi-layer system allowing us to identify the dissociation of bound vortex molecules.4 pages, 1 figure; revised version, to appear in Phys. Rev. LettSuperconductivitytext