Robustness of Spin Polarization in Graphene-Based Spin Valves

The decrease of spin polarization in spintronics devices under the application of a bias voltage is one of a number of currently important problems that should be solved. Here, an unprecedented robustness of the spin polarization in multilayer‐graphene spin valves at room temperature is revealed. Surprisingly, the spin polarization of injected spins is constant up to a bias voltage of +2.7 V and −0.6 V in positive‐ and negative‐bias voltage applications at room temperature, respectively, which is superior to all spintronics devices. This finding is induced by suppression of spin scattering due to an ideal‐interface formation. Furthermore, an important accordance between theory and experiment in molecular spintronics is found by observing the fact that the signal intensity in a local scheme is double that in a nonlocal scheme, as theory predicts, which provides construction of a steadfast physical basis in this field. Graphene spintronics is currently regarded as one of the most pivotal research topics in group‐IV spintronics. Here, an unprecedented robustness of the spin polarization in multilayer‐graphene spin valves is revealed: the spin polarization of the injected spins into the graphene is constant at room temperature. This finding can expand the possibilities of device design for future spin transistors. Furthermore, an important accordance between theory and experiment in molecular spintronics is found, which provides construction of a steadfast physical basis in this field.