A Mössbauer spectral study of some magnetic rare-earth iron intermetallic compounds

Author

Dimitri Hautot

Abstract

"In this thesis the Mössbauer spectra of Ce₂Fe₁₇H_x, where x is 0, 1,2, 3, 4, and 5, Pr₂Fe₁₇H_x where x is 0, 1, 2, 3, 4, and 5, Dy₂Fe₁₇H_x where x is 0, 1,2, 3, and 3.8, Tb₂Fe_17-xSi_x, where x is 0, 1, 2, and 3, and Nd₆Fe₁₃X, where X is Au, Ag, Cu, and Si, have been measured between 450 to 4.2 K.

Ce₂Fe₁₇ crystallizes in the R-3m space group and exhibits a helical magnetization from 225 to 90 K and a fan magnetization below 90 K. The helical magnetization was modeled in the Mössbauer spectra by a distribution of θ angles and hyperfine fields. The hyperfine parameters were found to have the expected temperature dependence and to be in good agreement with the hyperfine parameters found for the hydrides. Pr₂Fe₁₇H₅ is the first R₂Fe₁₇H_x compound to show an unusual change in the Mössbauer spectra below 155 K, a change which was attributed to the freezing of the motion of the 18g hydrogen from site to site on the Mössbauer time scale. Dy₂Fe₁₇H_x crystallizes in the hexagonal P6₃/mcm space group and exhibits a disorder of the 4e, 4f iron and 2c, 2d dysprosium site, a disorder which was modeled in the observed Mössbauer spectra.

Tb₂Fe_17-xSi_x shows an unexpected improvement in the magnetic properties with increasing silicon content in spite of a contration of the unit cell upon the substitution of iron by silicon.

Nd₆Fe₁₃Ar crystallizes in the I4|mmc space group and exhibits a basal magnetization for X = Ag, Au, and Cu. Nd₆Fe₁₃Si shows a spin reorientation from axial at 155 K towards basal at 80 K"--Abstract, page v.

Advisor(s)

Long, Gary J., 1941-

Committee Member(s)

Pringle, Oran Allan
Sinn, Ekkehard
Biolsi, Louis, Jr.
Grandjean, Fernande, 1947-
Isnard, Olivier

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Comments

The author thanks the Materials Research Division of the U. S. National Science Foundation for financial support through grant DMR-9521739.

Publisher

University of Missouri--Rolla

Publication Date

Summer 2000

Journal article titles appearing in thesis/dissertation

• A Mössbauer Spectral Study of the Magnetic Properties of Ce₂Fe₁₇ and its Hydrides
• Hydrogen Dynamics in the Hydrides of Pr₂Fe₁₇ as Revealed by Mössbauer Spectroscopy
• A Structural, Magnetic, and Mössbauer Spectral Study of Dy₂Fe₁₇ and its Hydrides
• A Mössbauer Spectral Study of Tb₂Fe₁₇ and the Tb₂Fe_17-xSi_x, Solid Solutions
• Mössbauer Spectral Study of Nd₆Fe₁₃X, where X is Cu, Ag, and Au, and the Spin-reorientation in Nd₆Fe₁₃Si
• A Mössbauer Spectral Study of the Nd₆Fe,,X Compounds, where X is Si, Cu, Ag, and Au
• Magnetic and Mössbauer Spectral Properties of the Compound Nd₆Fe₁₃Au

Pagination

xviii, 235 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2000 Dimitri Stanislas Hautot, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 7784

Print OCLC #

45965294

Recommended Citation

Hautot, Dimitri, "A Mössbauer spectral study of some magnetic rare-earth iron intermetallic compounds" (2000). Doctoral Dissertations. 1366.
https://scholarsmine.mst.edu/doctoral_dissertations/1366