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arXiv · 0905.4315

The role of hydrogen in room-temperature ferromagnetism at graphite surfaces

H. Ohldag·P. Esquinazi·E. Arenholz·D. Spemann·M. Rothermel·A. Setzer·T. Butz
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Abstract

We present a x-ray dichroism study of graphite surfaces that addresses the origin and magnitude of ferromagnetism in metal-free carbon. We find that, in addition to carbon $\pi$ states, also hydrogen-mediated electronic states exhibit a net spin polarization with significant magnetic remanence at room temperature. The observed magnetism is restricted to the top $\approx$10 nm of the irradiated sample where the actual magnetization reaches $ \simeq 15$ emu/g at room temperature. We prove that the ferromagnetism found in metal-free untreated graphite is intrinsic and has a similar origin as the one found in proton bombarded graphite.

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H. Ohldag, P. Esquinazi, E. Arenholz, D. Spemann, M. Rothermel, A. Setzer, T. Butz. 2009-05-27. The role of hydrogen in room-temperature ferromagnetism at graphite surfaces. https://doi.org/10.1088/1367-2630/12/12/123012

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