Spin transport and tunneling magnetoresistance in Thue-Morse bilayer graphene superlattice with two ferromagnetic electrodes

Abstract

We investigate the spin-polarized transport properties for magnetic junctions consisting of two ferromagnetic bilayer graphene (FBG) electrodes separated by a fourth-generation Thue-Morse bilayer graphene superlattice (TMBGS) or the corresponding periodic bilayer graphene superlattice (PBGS) under a uniform electric field. The spin conductance, spin polarization, and tunneling magnetoresistance (TMR) of the FBG/TMBGS/FBG junction are numerically calculated and compared with those of the FBG/PBGS/FBG junction. We find that the spin conductance can be greatly changed not only by the magnetization of the two FBG electrodes, but also by the exchange splitting energy. In the low energy range, the spin polarization and the TMR show drastic oscillations with increasing the Fermi energy. In the high energy range, the spin polarization and the TMR tend to be zero as the Fermi energy increases. Furthermore, compared to the FBG/PBGS/FBG junction, in the FBG/TMBGS/FBG junction, relatively large values of the TMR can be more easily obtained as the bias voltage increases.