The crystallographic and magnetic properties of SmyGd2-yFe17-xSix (0 ≤ x ≤ 3 and y = 1 and 1.5) solid solutions and their interstitial carbides have been investigated using x-ray diffraction and magnetic measurements. The SmyGd2-yFe17-xSix samples crystallized in the rhombohedral Th2Zn17 structure with less than 5 mol % of impurities. The unit cells of the mixed rare-earth (R) samples are smaller than those of Sm2Fe17 and Gd2Fe17. The carbided samples contain up to a total of 15 mol % of free iron, an iron suicide, and/or cubic Si5C3. The unit cells of the carbided samples are 1%-4% larger than those of the parent samples. For a given silicon concentration, the Curie temperatures (Tc) of SmyGd2-yFe17-xSix intermetallics are higher than those of the two end members. For example, the Tc of SmGdFe17 (280°C) is approximately 160° and 80° higher than that of Sm2Fe17 and Gd2Fe17, respectively. The Tc measured for the SmyGd2-yFe17-xSx samples, 280-290°C, are among the highest values observed for a R2Fe17-xMx intermetallic where M is a substituent other than cobalt. Except in the case of SmGdFe16SiCz (z unknown), the Tc of the carbided samples are 20%-25% higher than those of the parent samples. A Tc of 426°C and a magnetization of 120.6 emu/g observed for SmGdFe16SiCz are the highest values measured for the intermetallics investigated herein. As determined by x-ray diffraction studies of magnetically aligned samples, the easy axis of magnetization is parallel to the c axis.
P. C. Ezekwenna et al., "A Magnetic and Crystallographic Study of (Sm/Gd)₂(Fe/Si)₁₇Cz Solid Solutions," Journal of Applied Physics, vol. 87, no. 9, pp. 6716-6718, American Institute of Physics (AIP), May 2000.
The definitive version is available at https://doi.org/10.1063/1.372818
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© 2000 American Institute of Physics (AIP), All rights reserved.
01 May 2000