Neutron diffraction study on the crystal and magnetic structures of arc-melted PrFe10.5Mo1.1C0.4 alloy

The crystal and magnetic structures, especially the site occupation of C atoms in the crystal cell of arc-melted PrFe10.5Mo1.1C0.4 permanent magnetic alloy have been determined by means of powder neutron diffraction study. Rietveld analysis of the neutron diffraction data indicates that Mo atoms prefers the 8i site, about 76 percent of the C atoms occupy the 8i substitution site, and the other part of C atoms enter the 2b interstitial site. The exact molecular formula should be Pr(Fe10.575Mo1.250C0.1.75C0.055. It seems that the site occupation of C atoms in the ThMn12-type carbides depends not only on the kind of substitutional transition metals, but also on the components of the substitutional transition metals in the compounds. There are still amount of work to make systematic studies on the relation between them. The effect of C atoms on the magnetic properties is also discussed. (author)