High-Temperature Magnetism in Graphene Induced by Proximity to EuO.

Abstract

Addition of magnetism to spectacular properties of graphene may lead to novel topological states and design of spin logic devices enjoying low power consumption. A significant progress is made in defect-induced magnetism in graphene-selective elimination of p z orbitals (by vacancies or adatoms) at triangular sublattices tailors graphene magnetism. Proximity to a magnetic insulator is a less invasive way, which is being actively explored now. Integration of graphene with the ferromagnetic semiconductor EuO has much to offer, especially in terms of proximity-induced spin-orbit interactions. Here, we synthesize films of EuO on graphene using reactive molecular beam epitaxy. Their quality is attested by electron and X-ray diffraction, cross-sectional electron microscopy, and Raman and magnetization measurements. Studies of electron transport reveal a magnetic transition at TC* ≈ 220 K, well above the Curie temperature 69 K of EuO. Up to TC*, the dependence R xy( B) is strongly nonlinear, suggesting the presence of the anomalous Hall effect. The role of synthesis conditions is highlighted by studies of an overdoped structure. The results justify the use of the EuO/graphene system in spintronics.