Phys. Rev. Lett. 91, 227201 (2003)

P. Esquinazi, D. Spemann, R. Höhne, A. Setzer, K.-H. Han, and T. Butz

Abstract

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 and magnetic force microscopy reveal that the magnetic ordering is stable at room temperature.