Composition-controlled magnetic proximity effects in CoFe2O4-CoFe-reduced graphene oxide composites prepared by a simple single-step sonochemical reduction method

Abstract

A simple single-step sonochemical reduction method is used to prepare CoFe2O4-CoFe-reduced graphene oxide (rGO) composites (with varied amounts of CoFe2O4 and CoFe) under atmospheric conditions. The method enables in-situ reduction of graphene oxide (GO) to rGO and control of rGO content while the CoFe2O4-CoFe-rGO composites form. X-ray and electron diffraction and high-resolution electron microscopy revealed the formation of CoFe2O4-CoFe-rGO composites. The formation of the composites was further confirmed by Raman scattering analysis. Without rGO, an enhanced exchange coupling between soft CoFe and hard CoFe2O4 magnetic phases is observed. With rGO, tunable interfacial magnetic proximity-induced magnetization at the interface of CoFe2O4-CoFe and rGO is observed.