  The theoretical and experimental results concerning the thermodynamical and
low-frequency transport properties of hybrid structures, consisting of
spatially-separated conventional low-temperature superconductor (S) and
ferromagnet (F), is reviewed. Since the superconducting and ferromagnetic parts
are assumed to be electrically insulated, no proximity effect is present and
thus the interaction between both subsystems is through their respective
magnetic stray fields. Depending on the temperature range and the value of the
external field H_{ext}, different behavior of such S/F hybrids is anticipated.
Rather close to the superconducting phase transition line, when the
superconducting state is only weakly developed, the magnetization of the
ferromagnet is solely determined by the magnetic history of the system and it
is not influenced by the field generated by the supercurrents. In contrast to
that, the nonuniform magnetic field pattern, induced by the ferromagnet,
strongly affect the nucleation of superconductivity leading to an exotic
dependence of the critical temperature T_{c} on H_{ext}. Deeper in the
superconducting state the effect of the screening currents cannot be neglected
anymore. In this region of the phase diagram various aspects of the interaction
between vortices and magnetic inhomogeneities are discussed. In the last
section we briefly summarize the physics of S/F hybrids when the magnetization
of the ferromagnet is no longer fixed but can change under the influence of the
superconducting currents. As a consequence, the superconductor and ferromagnet
become truly coupled and the equilibrium configuration of this "soft" S/F
hybrids requires rearrangements of both, superconducting and ferromagnetic
characteristics, as compared with "hard" S/F structures.
