Signature of magnetism in 2D-chromia: 2D analog of the natural α-Cr2O3 mineral and its heterostructure with graphene

Abstract

The family of intrinsic 2D magnetic materials is consistently expanding day by day due to their numerous applications and easy availability. The latest member of the family is 2D-chromia – the 2D analog of the bulk chromia mineral (α-Cr₂O₃). In the present work, we have thoroughly explained and investigated its structural, electronic and magnetic properties. Our first-principles calculations show that it exhibits a ferromagnetic ground state with an appreciable magnetic moment. The large value of the magnetocrystalline anisotropy energy (MAE) leads to its stability against thermal fluctuations. We also show that due to the large radius of the Cr atom, exchange interactions dominate over Cr–O–Cr antiferromagnetic superexchange interactions that result in the existence of strong magnetic ordering in contrast to bulk chromia. However, the presence of a large band gap limits its application to a great extent. We have resolved this existing ambiguity by making its suitable van der Waals (vdW) heterostructure with the graphene. Our results indicate that the resulting materials may pave the way for spintronic applications and open up a new path for research in other 2D oxides of transition metals.