Anomalous Thermal Expansion in Substituted Nd₂Fe₁₇₋ₓSiₓ and Nd₂Fe₁₇₋ₓAlₓ Compounds

Author

X. D. Zhang
Mark G. Shumsky
William Joseph James, Missouri University of Science and TechnologyFollow
William B. Yelon, Missouri University of Science and TechnologyFollow

Abstract

The temperature dependencies of the lattice parameters were measured from room temperature to 400 °C for powders of the substituted compounds Nd₂Fe_17-xAl_x and ND₂Fe_17-xSi_x = 0,1,2,3, using high-temperature x-ray diffraction. All compounds crystallize in the rhombohedral Th₂Zn_17-type structure (space group R3^-m). Invar-type anomalies are found in the temperature dependence of a and c below the Curie temperatures, T_c, but featuring different substitution effects of Fe by Al and Si atoms, respectively. The Nd₂Fe_17-xAl_x and ND₂Fe_17-xSi_x compounds retain easy-plane anisotropies upon substitution up to x = 3. Therefore, the observed spontaneous volume magnetostrictions are due mainly to the isotropic exchange contribution of the iron sublattice. According to the localized model of exchange interactions in R-Fe compounds, the different substitution effects can be ascribed to the different preferential occupation tendencies of Al and Si atoms on the sites of the Th₂Zn_17-type structure.

Recommended Citation

X. D. Zhang et al., "Anomalous Thermal Expansion in Substituted Nd₂Fe₁₇₋ₓSiₓ and Nd₂Fe₁₇₋ₓAlₓ Compounds," IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers (IEEE), Jan 1995.

The definitive version is available at https://doi.org/10.1109/20.489602

Department(s)

Chemistry

Second Department

Physics

International Standard Serial Number (ISSN)

0018-9464

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1995 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 1995