Magnetic logic inverter from crossed structures of defect-free graphene with large unsaturated room temperature negative magnetoresistance

Introducing defects into graphene has been widely utilized to realize the negative magnetoresistance (MR) effect in graphene. However, the reported graphene negative MR exhibits only ~ 10% under 10 T at room temperature to date, which extremely limits the resolution of future spintronics devices. Moreover, intentional defect introduction can also cause unintentional degradation in graphene's intrinsic properties. In this paper, we report a magnetic logic inverter based on a crossed structure of defect-free graphene, resulting in a substantial gain of 4.81 mV/T while exhibiting room temperature operation. This crossed structure of graphene shows large unsaturated room temperature negative MR with an enhancement of up to 1, 000% at 9 T. A transition behavior between negative and positive MR is observed in this crossed structure and the transition temperature can be tuned by a ratio of the conductivity between in-plane and out-of-plane transport. Our results open an intriguing path for future two-dimensional spintronics device applications.