The structural evolution of cobalt nanoclusters synthesized in silica glass by ion implantation has been investigated upon thermal annealing. The samples were characterized by in-situ grazing incidence X-ray diffraction, exploiting a synchrotron radiation beam and following their evolution during thermal treatments in vacuo up to T=800 degrees C. Before heating, the system is composed of hcp Co nanocrystals; we have not detected the transition from hcp to fcc structure that in the bulk phase occurs around 420 degrees C; nevertheless, the differences in the diffraction pattern recorded at T=800 degrees C with respect to the corresponding one at room temperature suggest the presence of a second crystalline phase.
Thermal evolution of cobalt nanocrystals embedded in silica
MATTEI G;CANTON P;CATTARUZZA E;MAZZOLDI P.;VOMIERO A
2007-01-01
Abstract
The structural evolution of cobalt nanoclusters synthesized in silica glass by ion implantation has been investigated upon thermal annealing. The samples were characterized by in-situ grazing incidence X-ray diffraction, exploiting a synchrotron radiation beam and following their evolution during thermal treatments in vacuo up to T=800 degrees C. Before heating, the system is composed of hcp Co nanocrystals; we have not detected the transition from hcp to fcc structure that in the bulk phase occurs around 420 degrees C; nevertheless, the differences in the diffraction pattern recorded at T=800 degrees C with respect to the corresponding one at room temperature suggest the presence of a second crystalline phase.
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