Related papers: Magnetic order in Graphite: Experimental evidence,…
We provide evidence that proton irradiation of energy 2.25 MeV on highly-oriented pyrolytic graphite samples triggers ferro- or ferrimagnetism. Measurements performed with a superconducting quantum interferometer device (SQUID) and magnetic…
The search for macroscopic magnetic ordering phenomena in organic materials, in particular in pure graphite, has been one of the more exciting scientific activities working in the frontiers of physics, chemistry, and materials science. In…
The magnetic properties of disordered graphene and irradiated graphite are systematically studied using a combination of mean-field Hubbard model and first-principles calculations. By considering large-scale disordered models of graphene, I…
We investigate the magnetism in graphite by controlled oxidation. Our approach renders graphite an insulator while maintaining its structure. Fourier transform infrared spectroscopy and X-ray absorption near edge structure spectra reveal…
We demonstrate direct evidence for ferromagnetic order at defect structures in highly oriented pyrolytic graphite with magnetic force microscopy at room temperature. Magnetic impurities have been excluded as the origin of the magnetic…
We have prepared magnetic graphite samples bombarded by protons at low temperatures and low fluences to attenuate the large thermal annealing produced during irradiation. An overall optimization of sample handling allowed us to find Curie…
It has been a long-standing goal to create magnetism in a nonmagnetic material by manipulating its structure at the nanometer scale. This idea may be realized in graphitic carbon: evidence suggests magnetic states at the edges of graphene…
In this chapter we review the magnetic effects produced by proton irradiation on graphite, disordered carbon and fullerene films. The advantage of proton irradiation is twofold: it enables us to make an impurity analysis simultaneously to…
The conditions for spontaneous magnetization in a single graphene sheet are discussed in the context of Mermin-Wagner theorem. It is rigorously proved that at any nonzero temperature the graphene monolayer is nonmagnetic as long as its…
Magnetite, Fe$_3$O$_4$, displays a highly complex low temperature crystal structure that may be charge and orbitally ordered. Many of the recent experimental claims of such ordering rely on resonant soft x-ray diffraction at the oxygen K…
We have studied the magnetization of various, well characterized samples of highly oriented pyrolitic graphite (HOPG), Kish graphite and natural graphite to investigate the recently reported ferromagnetic-like signal and its possible…
A detailed magnetoresistance study of bulk and microflake samples of highly oriented pyrolytic graphite with a thickness of 25 $\mu$m to 23~nm reveals that the usually observed field-induced metal-insulator and electronic phase transitions…
Magnetic order emerging in otherwise non-magnetic materials as carbon is a paradigmatic example of a novel type of s-p electron magnetism predicted to be of exceptional high-temperature stability. It has been demonstrated that atomic scale…
We have measured the magnetic field and temperature dependence of the resistivity of several micrometers long and heterogeneously thick graphite sample. The magnetoresistance results for fields applied nearly parallel to the graphene planes…
We review our recent work on magnetic properties of graphite and related carbon materials. The results demonstrate that a structural disorder, topological defects, as well as adsorbed foreign atoms can be responsible for the occurrence of…
In the last years the number of nominally non-magnetic solids showing magnetic order induced by some kind of defects has increased continuously. From the single element material graphite to several covalently bonded non-magnetic compounds,…
Cervenka et al. have recently reported ferromagnetism along graphite steps. We present Magnetic Force microscopy (MFM) data showing that the signal along the steps is independent of an external magnetic field. Moreover, by combining Kelvin…
The arguments supporting the existence of the intrinsic magnetism in carbon-based materials including pure graphene were analyzed critically together with the numerous experimental evidences denying the magnetism in these materials. The…
The detailed analysis of the problem of possible magnetic behavior of the carbon-based structures was fulfilled to elucidate and resolve (at least partially) some unclear issues. It was the purpose of the present paper to look somewhat more…
We have investigated the variation in the magnetization of highly ordered pyrolytic graphite (HOPG) after neutron irradiation, which introduces defects in the bulk sample and consequently gives rise to a large magnetic signal. We observe…