title: pi-electron ferromagnetism in metal-free carbon probed by soft x-ray dichroism.
abstract: Elemental carbon represents a fundamental building block of matter and the possibility of ferromagnetic order in carbon has attracted widespread attention. However, the origin of magnetic order in such a light element is only poorly understood and has puzzled researchers. We present a spectromicroscopy study at room temperature of proton irradiated metal-free carbon using the elemental and chemical specificity of x-ray magnetic circular dichroism. We demonstrate that the magnetic order in the investigated system originates only from the carbon pi-electron system.
authors.affiliation: Stanford Synchrotron Radiation Laboratory, Stanford University, P.O. Box 20450, Menlo Park, California 94025, USA. hohldag@stanford.edu
authors.forename: H
authors.initials: H
authors.lastname: Ohldag
authors.forename: T
authors.initials: T
authors.lastname: Tyliszczak
authors.forename: R
authors.initials: R
authors.lastname: Höhne
authors.forename: D
authors.initials: D
authors.lastname: Spemann
authors.forename: P
authors.initials: P
authors.lastname: Esquinazi
authors.forename: M
authors.initials: M
authors.lastname: Ungureanu
authors.forename: T
authors.initials: T
authors.lastname: Butz
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002942:Circular Dichroism; D004583:Electrons; D007501:Iron / Q000737:chemistry*; D008280:Magnetics; D018625:Microscopy, Atomic Force; D013052:Spectrometry, X-Ray Emission
chemical_list: D002244:Carbon; D007501:Iron