Room temperature giant magnetoresistance in half-metallic CrC based two-dimensional tunnel junctions.

Two-dimensional (2D) magnetic materials inherit enormous potential to revolutionize next-generation spintronic technology. The majority of prior investigations using 2D ferromagnet-based tunnel junctions have shown encouraging tunnel magnetoresistance (TMR) at low temperatures. Using first-principles-based calculations, here we investigate the magnetic properties of commercially available CrC crystals at their monolayer limit and reveal their half metallicity properties far beyond room temperature. We then design hetero-multilayer structures combining CrC with graphene and hexagonal boron nitride (h-BN) and report their magnetoresistance using spin-polarized quantum transport calculations. While graphene based devices, adsorbed on the metal contact, reveal a very high TMR (1200%), it can be further increased to 1500% by changing the barrier layer to h-BN. The dependence of TMR on the number of barrier layers and different metallic electrode materials (Ti, Ag, and Au) are also studied. Our investigation suggests that CrC based spin valves can serve as the perfect building blocks for room temperature all-2D spintronic devices.