Magnetism in reduced graphene oxide-germanium quantum dot nanocomposite

Abstract

Graphene is characterized by inherent weak spin-orbit and hyperfine couplings which suit it for spin transport electronics.  But its application in spintronics is limited by its lack of intrinsic magnetic moments coupled with the long spin relaxation lengths that result from the hyperfine coupling.  However, localized magnetic moments can be induced in graphene by the formation of structural defects which include vacancies, edges, and adatoms.  In this study, we report high defect-induced magnetization in reduced graphene oxide attained via germanium adatoms.  The nanocomposites magnetization has both paramagnetic and ferromagnetic contributions.  The evolution of the magnetic moments in the nanocomposites and the coercivity showed marked dependence on the Ge quantum dots size and concentration.  Thus, our findings depict that strong defect-induced magnetism can be achieved in graphene through heavy element functionalization.