Realization of "single-atom ferromagnetism" in graphene by Cu-N4 moieties anchoring

Abstract

Ferromagnetism in graphene-based materials has attracted much attention because of their potential applications in future spintronic devices. Here, we propose a strategy to induce "single-atom ferromagnetism" in three-dimensional graphene by Cu anchoring, wherein the Cu atoms are isolated with Cu-N4 moieties, as demonstrated by extended x-ray absorption fine structure and spherical aberration correction transmission electron microscope measurements. Superconducting quantum interference device and x-ray magnetic circular dichroism measurements reveal the clear ferromagnetism of single-atom Cu-anchored graphene with saturation magnetization of 1.15 emu/g at 2 K and 0.05 emu/g at 300 K, suggesting its promising applications in spintronics. Additionally, density functional theory (DFT) calculations prove that the Cu-N4 group can produce net magnetic moments and that the system favors the ferromagnetic stable state. More importantly, our DFT calculations show that anchoring single atoms of other transition metals can also realize single-atom ferromagnetism in graphene.