Theoretical investigation of interface atomic structure of graphene on NiFe alloy substrate

Abstract

Two processes have been proposed to fabricate graphene/NiFe alloy interfaces for tunneling magnetoresistance devices. One is the transfer of graphene and the other is the evaporation of alloys onto graphene. The formation energy of a NiFe alloy substrate and the adsorption energy of graphene on the NiFe alloy substrate are investigated by a density functional theory calculations to reveal the difference in the atomic structure of the interface between the two processes. It is found that Ni-rich surfaces are preferable for the bare substrate, whereas Fe surfaces are stable for the graphene adsorbed on the substrate. This result indicates that the composition ratio of the surface layer depends on the interface fabrication process.