Understanding the effect of vacancy defects on spin transport in CrO2-graphene-CrO2 magnetic tunnel junction

In this paper, we investigate the effect of vacancy defects on spin transport in graphene-based magnetic tunnel junction (MTJ). An increase in conductance was seen in vacancy-defected MTJ structure which is in contrast to the results reported in past where a decrease in conductance with vacancy was observed for graphene sheets. This increase in conductance may be due to the use of CrO2 half-metallic ferromagnet (HMF) electrodes instead of metallic or ferromagnet (FM) electrodes. Furthermore, high tunnel magnetoresistance (TMR) similar to 99% and perfect spin filtration was obtained for both vacancy-defected and no-defect (pristine) MTJ structures. The TMR in vacancy-defected structure is seen to decrease by 6.2% and by 13% at bias voltages of 1.2V and 1.4V, when compared to TMR in no-defect MTJ structure.