  We investigate Andreev transport through a quantum dot attached to two
external ferromagnetic leads and one superconducting electrode. The transport
properties of the system are studied by means of the real-time diagrammatic
technique in the sequential tunneling regime. To distinguish various
contributions to Andreev current we calculate the current cross-correlations,
i.e. correlations between currents flowing through two junctions with normal
leads. We analyze dependence of current cross-correlations on various
parameters of the considered model, both in linear and nonlinear transport
regimes. The processes and mechanisms leading to enhancement, suppression or
sign change of current cross-correlations are examined and discussed.
Interestingly, our results show that for specific transport regimes splitted
Cooper pair results in two uncorrelated electrons. However, utilizing
ferromagnetic leads instead of non-magnetic electrodes can result in positive
current cross-correlations.
