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In this work we will focus on the effects produced by topological disorder on the electronic properties of a graphene plane. The presence of this type of disorder induces curvature in the samples of this material, making quite difficult the application of standard techniques of many-body quantum theory. Once we understand the nature of these defects, we can apply ideas belonging to quantum field theory in curved space-time and extract information on physical properties that can be measured experimentally. [ABSTRACT FROM AUTHOR]

Magnetic correlations in carbon-based materials have been reported for many years, but the lack of reproducibility have aroused scepticism about this topic. However, in recent years, the improvement of the characterization techniques has allowed the observation of ferromagnetism and the precise measurement of the impurity amounts in different samples of HOPG and Kish graphite [1]. Besides the ferromagnetic hysteresis loops [2] reported at room temperature, the enhancement of ferromagnetic behavior by proton bombardment of graphite has been observed in samples with an amount of impurities much lower than that needed to produce the saturation magnetization measured [3]. Irradiation induced magnetism in carbon nanostructures has been reported by N and C implantation [4]. A relation between the magnetic properties of pure bulk ferromagnetic graphite and the topographic defects introduced in the pristine material have been reported by comparison of atomic force microscopy (AFM) images and magnetic force microscopy (MFM) [5]. Soft X-ray dichroism spectromicroscopy has been used to analyze the magnetic order of metal free carbon films. A clear evidence of intrinsic ferromagnetic order at room temperature has been obtained in these carbon films that have been irradiated by a focused proton beam [6]. All these experiments suggest that there is a relation between topological defects in the lattice induced by irradiation and the ferromagnetic correlations [6]. We will study the ferromagnetism in a two-dimensional graphene plane by considering disorder, vacancies, and defects in the atomic network. [ABSTRACT FROM AUTHOR]

The discovery of nanostructured forms of molecular carbon has led to renewed interest in the varied properties of this element. Recent experiments and theoretical studies have suggested that electronic instabilities in pure graphite may give rise to superconducting and ferromagnetic properties, even at room temperature. Magnetic carbon could be used to make inexpensive, metalfree magnets for applications in medicine and biology, nanotechnology andtelecommunications. The following topics in the invited presentations to the minisymposium have been included in these proceedings: The state of the art of magnetism in nanographite is reviewed in two papers from the point of view of experimentalists (T. Makarowa and M.A. Ramos). The theoretical support is presented in the report by M.P. Lopez-Sancho, M.A.H. Vozmediano, F. Stauber, and F. Guinea. A. Cortijo discusses the electronic properties of topological defects in graphene, and F. Guinea presents a transistor effect in bilayer graphene. An additional presentation by L. Pisani on numerical studies of graphene nanoribbons could not be included in this volume. [ABSTRACT FROM AUTHOR]