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The quaternary system Sm-Fe-Mo-Al and the effect of Al substitution on magnetic and structural properties of its ThMn12 phase

Simon, D. and Wuest, H. and Koehler, T. and Senyshyn, A. and Ehrenberg, H. and Gutfleisch, O. (2019):
The quaternary system Sm-Fe-Mo-Al and the effect of Al substitution on magnetic and structural properties of its ThMn12 phase.
In: Journal of Alloys and Compounds, ELSEVIER SCIENCE SA, LAUSANNE, SWITZERLAND, pp. 301-307, 770, ISSN 09258388, DOI: 10.1016/j.jallcom.2018.08.030, [Online-Edition: https://doi.org/10.1016/j.jallcom.2018.08.030],
[Article]

Abstract

The Fe-rich corner of the quaternary system Sm-Fe-Mo-Al is studied at isothermal conditions. The phase equilibria of ferromagnetic with adjacent phases, especially , are observed for 1000 °C. Existence ranges are studied by SEM/EDX on samples with various compositions. Magnetic and structural properties were obtained by VSM(PPMS) as well as Permagraph measurements while structural relations were tracked by XRD. Al can be substituted for Fe up to x = 6.5 accompanied by a decrease in high field (8 MA/m 10 T) polarization from 0.66 T (x = 0.0) to 0.44 T (x = 2.0). Respective Curie temperatures of and initially increase with Al content reaching a maximum of 125 °C at x = 0.5 and 135 °C at x = 1.0, respectively. Further Al substitution decreases TC. The coercive fields of optimally annealed nanocrystalline powders decrease slightly from 153 kA/m for x = 0.0–139 kA/m for x = 0.8 and drops to 38 kA/m for x = 2.0. XRD data indicates that lattice parameters of continuously increase with Al content. The simultaneous refinement of X-ray and neutron diffraction patterns confirms that Mo prefers 8i sites in the ThMn12 structure and that Al occupies equally 8i and 8j in a ratio of 1:2.

Item Type: Article
Erschienen: 2019
Creators: Simon, D. and Wuest, H. and Koehler, T. and Senyshyn, A. and Ehrenberg, H. and Gutfleisch, O.
Title: The quaternary system Sm-Fe-Mo-Al and the effect of Al substitution on magnetic and structural properties of its ThMn12 phase
Language: English
Abstract:

The Fe-rich corner of the quaternary system Sm-Fe-Mo-Al is studied at isothermal conditions. The phase equilibria of ferromagnetic with adjacent phases, especially , are observed for 1000 °C. Existence ranges are studied by SEM/EDX on samples with various compositions. Magnetic and structural properties were obtained by VSM(PPMS) as well as Permagraph measurements while structural relations were tracked by XRD. Al can be substituted for Fe up to x = 6.5 accompanied by a decrease in high field (8 MA/m 10 T) polarization from 0.66 T (x = 0.0) to 0.44 T (x = 2.0). Respective Curie temperatures of and initially increase with Al content reaching a maximum of 125 °C at x = 0.5 and 135 °C at x = 1.0, respectively. Further Al substitution decreases TC. The coercive fields of optimally annealed nanocrystalline powders decrease slightly from 153 kA/m for x = 0.0–139 kA/m for x = 0.8 and drops to 38 kA/m for x = 2.0. XRD data indicates that lattice parameters of continuously increase with Al content. The simultaneous refinement of X-ray and neutron diffraction patterns confirms that Mo prefers 8i sites in the ThMn12 structure and that Al occupies equally 8i and 8j in a ratio of 1:2.

Journal or Publication Title: Journal of Alloys and Compounds
Volume: 770
Publisher: ELSEVIER SCIENCE SA, LAUSANNE, SWITZERLAND
Uncontrolled Keywords: ThMn12 phase, Al substitution, Permanent magnet, Structural analysis, Kerr microscopy
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Functional Materials
Date Deposited: 19 Nov 2018 08:24
DOI: 10.1016/j.jallcom.2018.08.030
Official URL: https://doi.org/10.1016/j.jallcom.2018.08.030
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