Spin filtering device through designing the normal/ferromagnetic/normal graphene superlattices

Quantum transport properties of normal/ferromagnetic/normal graphene (NG/FG/NG) superlattices exposed to ferromagnetic graphene connected to a gate electrode are investigated via the transfer matrix method. Here, we calculate the role of parameters including well, and barrier width in the spin current. In addition, the Fermi energy and gate voltage effects on raising and tunable spin splitting have been investigated. Calculations demonstrate that the exchange field applied to the region of the ferromagnetic graphene device, by changing the chemical potential, results in an oscillatory behavior. We found that it opens a gap and indicates a metal-insulator phase transition by enhancing unit cells (N = 100). Meanwhile, results reveal that by tuning the gate voltage, we can control the spin currents, as a result, it may allow for the filtering of up or down spins. Further, increasing the barrier width and Fermi energy reveals that the spin current is reversible. Furthermore, this computational research found that quantum modulating behavior by controlling wells, barrier widths, and chemical energy in the device. The results might have potential applications in designing nano-devices and developing spintronic systems.