Europhys. Lett.
Volume 65, Number 1, January 2004
Page(s) 130 - 136
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 December 2003
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

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

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.

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.

© EDP Sciences 2004