A Mössbauer Spectral Study of Nd₆Fe₁₃X, Where X Is Cu, Ag, and Au and of the Spin Reorientation in Nd₆Fe₁₃Si

Author

Dimitri Hautot
Gary J. Long, Missouri University of Science and TechnologyFollow
Fernande Grandjean, Missouri University of Science and TechnologyFollow
C. H. De Groot
K. H. Buschow

Abstract

The Mössbauer spectra of Nd₆Fe₁₃X, where X is Si, Cu, Ag, and Au, have been measured between 80 and 500 K. A model corresponding to a basal alignment of the magnetic moments leads to excellent, internally consistent, fits for the Cu, Ag, and Au compounds. The resulting temperature dependences of the spectral hyperfine parameters are uniform and reveal for each Fe site the expected correlations between the isomer shift and the Wigner-Seitz cell volume and the hyperfine field and the number of Fe near neighbors. For Nd₆Fe₁₃Si, a different model must be used because of the presence of a spin reorientation below 155 K. Above 155 K, because of the axial alignment of the moments, and in agreement with the 295 K powder neutron diffraction results, the spectra can be analyzed with four sextets. Below 155 K, five additional sextets are required to fit the spectra because of a progressive transition towards a basal alignment of the Fe moments. At 80 K the mixed magnetic phase is 75% basal and 25% axial, whereas at 110 K the mixture is 50:50. The hyperfine parameters of the basal and axial sextets found for Nd₆Fe₁₃Si are consistent with those found for the basal Cu, Ag, and Au compounds and those observed for basal Nd₆Fe₁₃Sn. The lattice properties of the compounds, obtained from the temperature dependences of the isomer shift and the spectral absorption area, are consistent with the Wigner-Seitz cell volumes and the bonding of each crystallographically distinct Fe site. The magnetic anisotropy of a variety of Nd₆Fe₁₃X compounds is controlled by the s-p hybridization of the Nd-X bonds, a hybridization which is very sensitive to the electronic configuration of X.

Recommended Citation

D. Hautot et al., "A Mössbauer Spectral Study of Nd₆Fe₁₃X, Where X Is Cu, Ag, and Au and of the Spin Reorientation in Nd₆Fe₁₃Si," Journal of Applied Physics, vol. 83, no. 3, pp. 1554 - 1562, American Institute of Physics (AIP), Feb 1998.

The definitive version is available at https://doi.org/10.1063/1.366865

Department(s)

Chemistry

International Standard Serial Number (ISSN)

0021-8979

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 1998 American Institute of Physics (AIP), All rights reserved.

Publication Date

01 Feb 1998