Enhancement and switch effect of equal-spin Andreev reflection in ferromagnet/insulator/Ising superconductor junctions.

We study the property of equal-spin Andreev reflection (ESAR) in the ferromagnet/insulator/Ising superconductor junction where Ising spin-orbit coupling is taken into account in the insulator. It is found that the ESAR exhibits a regular oscillation with the insulating barrier, the amplitude and period of which can be effectively controlled by the chemical potentials. Compared to that in the ferromagnet/Ising superconductor junction, the ESAR is greatly increased due to the resonant mode, suggesting an enhanced spin-triplet pairing. As an application, the proposed junction may work as a switch to turn on and off the ESAR. Furthermore, the insulating barrier does not change the magnetoanisotropic period of ESAR because of the invariant symmetry of the system, however, the magnetoanisotropy is strengthened.