  In this work, it is considered a nanostructure composed by a quantum dot
coupled to two ferromagnets and a superconductor. The transport properties of
this system are studied within a generalized mean-field approximation taking
into account proximity effects and spin-flip correlations within the quantum
dot. It is shown that the zero-bias transmittance for the co-tunneling between
the ferromagnetic leads presents a dip whose height depends on the relative
orientation of the magnetizations. When the superconductor is coupled to the
system, electron-hole correlations between different spin states leads to a
resonance in the place of the dip appearing in the transmittance. Such an
effect is accompanied by two anti-resonances explained by a leakage of
conduction channels from the co-tunneling to the Andreev transport. In the
non-equilibrium regime, correlations within the quantum dot introduce a
dependence of the resonance condition on the finite bias applied to the
ferromagnetic leads. However, it is still possible to observe signatures of the
same interference effect in the electrical current.
