A Magnetic, Neutron-diffraction, and Mössbauer Spectral Study of the Ce₂Fe₁₇₋ₓSiₓ Solid Solutions

Author

D. P. Middleton
Sanjay R. Mishra
Gary J. Long, Missouri University of Science and TechnologyFollow
Oran Allan Pringle, Missouri University of Science and TechnologyFollow
Zhongbo Hu
William B. Yelon, Missouri University of Science and Technology
Fernande Grandjean, Missouri University of Science and TechnologyFollow
K. H. J. Buschow

Abstract

The magnetic properties of a series of Ce₂Fe_17-xSi_x solid solutions with x equal to 0.0, 0.23, 0.4, 0.6, 0.8, 1.02, 1.98, and 3.20 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. An x-ray-diffraction study indicates that the compounds adopt the rhombohedral Th₂Zn ₁₇-type structure. The substitution of silicon for iron in Ce ₂Fe₁₇ leads to a contraction of the a axis by 0.2%, an expansion of the c axis by 0.2%, and a consequent reduction of the unit-cell volume by about 0.2% per substituted silicon. Magnetization studies indicate that the Curie temperature increases uniformly from 238 K for Ce ₂Fe₁₇ to 455 K for Ce₂Fe₁₄Si₂. Powder neutron-diffraction results, obtained at 295 K, indicate both that the silicon atoms preferentially occupy the 18h sites and that the iron moments increase with increasing silicon content, an increase which is related to the increase in Curie temperature. The Mössbauer spectra have been fit with a binomial distribution of the near-neighbor environments in terms of a maximum hyperfine field H_max for an iron with zero silicon near neighbors, and a decremental field ΔH per silicon near neighbor. The compositional independence of both the weighted average maximum hyperfine field and of the decremental field indicates that the silicon acts as a magnetic hole, a hole which does not perturb the magnetic moments at the iron sites. The compositional dependence of the weighted average isomer shift is explained in terms of an interband mixing of the iron 4s and silicon 2p bands, due to the reduction of the iron 18h bond lengths. This interband mixing affects the charge but not the spin distribution at the iron sites.

Recommended Citation

D. P. Middleton et al., "A Magnetic, Neutron-diffraction, and Mössbauer Spectral Study of the Ce₂Fe₁₇₋ₓSiₓ Solid Solutions," Journal of Applied Physics, vol. 78, no. 9, pp. 5568 - 5576, American Institute of Physics (AIP), Nov 1995.

The definitive version is available at https://doi.org/10.1063/1.359678

Department(s)

Chemistry

Second Department

Physics

International Standard Serial Number (ISSN)

0021-8979

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 1995 American Institute of Physics (AIP), All rights reserved.

Publication Date

01 Nov 1995