Mertins, H.; Jansing, C.; Gilbert, M.; Krivenkov, M.; Sanchez-Barriga, J.; Varykhalov, A.; Rader, O.; Wahab, H.; Timmers, H.; Gaupp, A.; Tesch, M.; Sokolov, A.; Legut, D.; Oppeneer, P.: Magneto-optical reflection spectroscopy on graphene/Co in the soft x-ray range. Journal of Physics: Conference Series 903 (2017), p. 012025/1-4
10.1088/1742-6596/903/1/012025
Open Access Version
Abstract:
The existence of ferromagnetic ordering in graphene on cobalt is demonstrated by means of resonant magnetic reflection spectroscopy exploiting the transversal magneto-optical Kerr-effect (T-MOKE). Using linearly polarized synchrotron radiation in the soft x-ray range with energies spanning the carbon 1s edge, the π- and σ- bonds of graphene were excited individually, showing that magnetism in graphene is carried by the π – orbitals. Magnetic signals were detected over a wide energy range from 257 – 340 eV with a T-MOKE peak value of 1.1 % at the π – resonance energy near 285 eV. By comparison with corresponding spectra measured at the 2p edges of the Co substrate, a large induced magnetic moment of 0.14 μB was derived for graphene. Individual hysteresis curves monitored at the Co 2p and C 1s edges show that the carbon magnetism is induced by the Co substrate.