ISSN:
1434-6036
Keywords:
PACS. 61.46.+w Clusters, nanoparticles, and nanocrystalline materials - 61.12.Ex Neutron scattering techniques (including small-angle scattering) - 61.72.Mm Grain and twin boundaries
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: By means of small-angle neutron scattering the microstructure of two nanocrystalline Pd samples (prepared by inert gas condensation) has been studied at room temperature in a Q-range from [0pt] to [0pt] . An additional subsequent doping of the two samples with H as well as with D (concentrations 〈 4 at%) caused contrast variations that provided more detailed structural information. The measured scattering intensity was modeled by a Porod contribution from large heterogenities (e.g. pores) and a contribution from spherical grains with a log-normal distribution of their radii. To account for the presence of grain boundaries, the grains were considered to be surrounded by a shell with a reduced Pd density and a thickness half as large as the thickness of the grain boundaries. For the above model, the data of the H-doped, D-doped and undoped sample were simultaneously fitted with one single set of adjustable parameters. The fits yielded for the two samples volume-weighted mean grain radii of 10 nm and 13 nm. The values for the grain boundary thickness lie between 0.2 and 0.8 nm. Almost all of the H- and D-atoms are, at low hydrogen concentrations, located in the grain boundaries.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100510070138
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