19 – Induced Magnetic Order by Ion Irradiation of Carbon-based Structures

This chapter studies induced magnetic order by ion irradiation of carbon-based structures. Proton irradiation can trigger magnetic ordering in graphite. The results after proton irradiation show that magnetic ordering exists in a carbon structure without the influence of magnetic ions. There is a negligible influence of the topography onto the magnetic signal, and the magnetic signal depends on the implanted charge, proton current, and probably also on the carbon structure. Hydrogenated nanographite can have a spontaneous magnetization due to different numbers of mono- and dihydrogenated carbon atoms. Theoretical simulations indicate that a magnetic ordered state should be easier to achieve with a mixture of carbon–hydrogen bonds than fluorinated nanographite. Muon spin rotation/relaxation experiments indicate that a positive muon in graphite triggers a local magnetic moment around it. Hydrogen may also play an important role in the magnetic ordering found in fullerenes.