Influence of the Silicon Composition on the Crystallographic Properties of the New Ferromagnetic Ternary Silicides U2Fe17-ySiy (3.3 ≤ y ≤ 4.5) and U2Co15Si2
✍ Scribed by T. Berlureau; P. Gravereau; B. Chevalier; J. Etourneau
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 279 KB
- Volume
- 104
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
After melting and quenching, the ternary silicides (\mathrm{U}{2} \mathrm{Fe}{11-y} \mathrm{Si}{y}) exist for (3.3 \leq y \leq 4.5) but they partially decompose after annealing at (850-900^{\circ} \mathrm{C}). Their crystal structure, determined by (\mathrm{X})-ray diffractometry on both single crystals and powder, derives from the hexagonal (\mathrm{Th}{2} \mathrm{Ni}{1})-type but depends strongly on the silicon content. For (y=3.7) some uranium sites are partially replaced by pairs of iron atoms and conversely. This structure shows some similarities to that observed for the binary compound (\mathrm{Ho}{2} \mathrm{Fe}{17}). On the other hand, for (y=4.2), all the uranium atoms and pairs of iron atoms are statistically distributed. In contrast, the ternary silicide (\mathrm{U}{2} \mathrm{Co}{15} \mathrm{Si}{2}), which is obtained as single phase after annealing at (850^{\circ} \mathrm{C}), adopts the (\mathrm{Th}{2} \mathrm{Ni}{1})-type structure. In all compounds, ison or cobalt atoms of the pair are never substituted by silicon atoms. 1993 Academic Press, Inc.