The influence of iron, fluorine and boron implantation on the magnetic properties of graphite

Magnetic order in graphite: Experimental evidence, intrinsic and extrinsic difficulties

“…In a recently published study the magnetic properties of HOPG samples after implantation of Fe have been studied [17]. No particular influence on the ferromagnetic properties of HOPG was observed after up to $4000 mg=g (0.08 at%) Fe concentration in the implanted region.…”

“…However, several facts appear to rule out this possibility. Measurements at different temperatures indicate that the AMR effect decreases with temperature with a dependence incompatible with a paramagnetic state (note that SQUID measurements show that the paramagnetism produced by irradiation follows the Curie 1=T law [12,13,17]). From the AMR data one can estimate the change of the magnetization at saturation M s assuming that M s pðMRÞ 1=2 at high enough fields.…”

Anisotropic magnetism of graphite irradiated with medium-energy hydrogen and helium ions

“…12 Therefore vacancies, [13][14][15] interstitials, [16][17][18] edges, [19][20][21] adsorption defects, 22 hydrogen complexes with vacancies or adatoms, [23][24][25] and other types of disorder 26,27 have been regarded as sources for creating unpaired carbon atoms in the lattice. Still, there is a lack of clarity whether the chemical nature of projectiles is of importance, since successful experiments were reported for hydrogen, 11,28 nitrogen, 28 and carbon, 28,29 whereas implantations with iron, 30,31 boron and fluorine, 31 and helium [32][33][34] were reported not to trigger magnetic ordering. Some problems concern the reproducibility of the experiments with the MeV-proton bombardment: the magnetic data 11 were confirmed by subsequent publications, 28,[30][31][32][33]35,36 but in other groups 34,37 only paramagnetic response was registered.…”

Paramagnetic Properties of Metal‐Free Boron‐Doped Graphene Quantum Dots and Their Application for Safe Magnetic Resonance Imaging

“…Localized spins in a high boron concentration region behave like isolated spins, therefore, leading to the formation of paramagnetic centers. [46] …”