Spin-polarized equal-spin Andreev reflection in antiferromagnetic graphene.

The transport properties of the graphene-based antiferromagnet/insulator/ferromagnet/superconductor junction with noncollinear magnetic moments are theoretically investigated under the Bogoliubov-de Gennes equation. By introducing a mass term into the antiferromagnetic region, the spin-polarized equal-spin Andreev reflection (EAR) can be achieved for all voltages in the subgap region, free from any interference from the opposite-spin Andreev reflection (OAR). The transition from the retro EAR to the specular EAR can be realized by adjusting the Fermi level within the antiferromagnetic region. The perfect EAR can be obtained, suggesting an efficient equal-spin pairing correlation. Furthermore, we note that the EAR exhibits magnetoisotropy with an in-plane ferromagnetic exchange field, which is opposite to the results in a ferromagnet/ferromagnet/superconductor junction. [ABSTRACT FROM AUTHOR]