**4. Conclusion**

We have theoretically investigated the subgap transport properties of a hybrid nanosystem consisting of an interacting QD connected to one superconducting lead and two ferromagnetic leads. On the basis of the finite-*U* slave boson mean field approach and the NGF method, we find markedly rich transport features ascribed to the competition among the Kondo correlation, superconducting proximity effect, and spin polarization of electrodes. In the case of weak superconducting proximity coupling, the Kondo-correlated state can still be built, leading to a single zero-bias peak in the voltage-dependent differential conductance. However, the peak height drops down gradually with increasing Γ*<sup>s</sup>*, and when Γ*s* ≥ 1.0, a non-zero peak appears. Such strong proximity coupling induces linear cross conductance which is negative in the Kondo region. Spin polarization can further enhance the opposite current response in the right lead (more negative cross conductance) in the AP configuration, because such a configuration is advantageous to the emergence of CAR. In contrast, in the P configuration, the rising spin polarization *p* blocks the CAR process and also splits the Kondo peak, such that the linear local conductance exhibits four peaks when Γ*s* ≥ 1.0, and the linear cross conductance reduces to the normal positive conductance more rapidly.

**Author Contributions:** Conceptualization, B.D.; Data curation, C.L.; Funding acquisition, B.D.; Investigation, C.L. and B.D.; Supervision, B.D. and X.-L.L; Writing—review & editing, B.D.

**Funding:** National Natural Science Foundation of China : 11674223.

**Acknowledgments:** This work was supported by Projects of the National Science Foundation of China under Grant No. 11674223.

**Conflicts of Interest:** The authors declare no conflict of interest.
