  The aim of this paper is to explain the non monotonic temperature dependence
of the self-consistent superconducting gap of
ferromagnet/superconductor/ferromagnet (F/S/F) trilayers with weak ferromagnets
in the parallel alignment (equivalent to F/S bilayers). We show that this is
due to Andreev bound states that compete with the formation of a minigap. Using
a recursive algorithm we discuss in detail the roles of various parameters
(thicknesses of the superconductor and ferromagnets, relative spin orientation
of the ferromagnets, exchange field, temperature, disorder, interface
transparencies).
