Magnetoresistance effect realized in current-in-plane Van der Waals spin valve structure by electrically switchable magnetization

Abstract

We present a device concept for magnetoresistance (MR) effect in which two Van der Waals (vdW) spin valves are used as the left and right ferromagnetic (FM) leads connected by a bilayer graphene as the channel material of the central scattering region. Unlike conventional current-perpendicular-to-plane magnetic tunnel junction consisting of two FM thin films with a thin insulating barrier sandwiched between them, the FM leads in our proposed current-in-plane MR device are vdW spin valves. This is important because the application of an out-of-plane electric field allows control of the direction and magnitude of the magnetization in vdW spin valves. Moreover, we show that the oscillatory behavior is found in the MR and conductance as the height (depth) of the barrier (well) of the scattering region with the p(n)-doping increase, or the width of the scattering region increase. Remarkably, when the potential barrier is present, the oscillation magnitude of MR is considerable and can be changed from positive to negative value, whereas for the potential well, the oscillation amplitude is relatively small and is always positive. Therefore, we hope that this device configuration with electrically tunable large MR can open up new possibilities for future lower power magneto-electric devices since no current-induced magnetization switching.