Muon spin relaxation as a probe of potential carbon-based hydrogen absorbers

T. P. Blach; E. MacA. Gray

doi:doi:10.1209/epl/i2003-10054-x

Europhys. Lett., 65 (1) , pp. 130-136 (2004)
DOI: 10.1209/epl/i2003-10054-x

Muon spin relaxation as a probe of potential carbon-based hydrogen absorbers

T. P. Blach and E. MacA. Gray

Physics Group, School of Science, Griffith University - Brisbane 4111, Australia

E.Gray@griffith.edu.au

(Received 7 August 2003; accepted in final form 28 October 2003)

Abstract
Literature reports of hydrogen absorption by nanostructured carbons range from nothing to tens of weight percent. We studied pristine graphite and two potassium-graphite intercalation compounds (GICs) using muon spin relaxation ( $\mu$ SR), because the positive muon is expected to behave like a light hydrogen isotope. The graphite did not trap muons, but at low temperatures a component of the $\mu$ SR spectrum from the two GICs could only be modelled by the Kubo-Toyabe function. This result demonstrates that muons were trapped by these samples and implies that $\chem{H}$ atoms would also be localised in these traps, in qualitative agreement with accepted hydrogen absorption results. Thus $\mu$ SR is confirmed to be a valuable probe of the relative ability of carbon-based samples to bind hydrogen atoms.

PACS
76.75.+i - Muon spin rotation and relaxation.
81.05.Uw - Carbon, diamond, graphite.
82.75.-z - Molecular sieves, zeolites, clathrates, and other complex solids.

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