Spin-dependent barrier effects on the transport properties of graphene-based normal metal/ferromagnetic barrier/d-wave superconductor junction

Abstract

Using the extended Blonder-Tinkham-Klapwijk formalism, the spin-dependent transport properties in a graphene-based normal metal/ferromagnetic barrier/d-wave superconductor (NFBd-wave) junction have been studied theoretically. Here, we have mainly studied the influences of spin-dependent barrier and rotation angle of d-wave superconducting order parameter (α) on the charge and spin conductance. It is found that the rotation angle has a strong effect on the amplitude and phase of the charge conductance oscillations. As a remarkable result, we obtained that because of the spin-dependent barrier (FB), the rotation angle cannot suppress the zero-bias charge conductance and for the maximum rotation angle α=π/4, the charge conductance shows oscillatory behavior which is different from similar non-spin-dependent barrier junctions. We have also shown that the spin filtering application of this junction is drastically changed by the rotation angle α. As α increases, the spin filtering application enhances, being strongest for α=π/4. At last, we propose an experimental setup to detect our predicted effects. © 2014 Elsevier B.V.