Magnetism of nano-graphite

Abstract

This chapter discusses the magnetism of the nano-sized graphite using—the activated carbon fibers (ACFs) and the heat-treated nano-diamond particles. The structure of ACFs can be described by a 3D disorder network of nanographites, where each nano-graphite domain consists of the stacked 3–4 graphene sheets—having a mean size of 3 nm. The prepared ACFs exhibit Coulomb gap variable-range hopping conduction, revealing the essential role of the charging effects of the nano-graphite domains—where the magnetism is associated with the edge-state spins. The spin-glass-like disordered magnetism appears near a heat-induced insulator–metal transition, and is related to the random strengths of the inter-nano-graphite anti-ferromagnetic interactions—mediated by the p-conduction carriers. Fluorination of the ACFs generates localized spins of the sp3-defects at the expense of the edge-state spins. The heat-treatment of the diamond nano-particles converts them to the carbon nano-particles, with complete graphitization taking place around 1600°C. The itinerant p-electron system of the graphite is gradually developed with the heat-treatment.