Journal Article

FZJ-2019-05189

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effect of grain-boundary diffusion process on the geometry of the grain microstructure of Nd − Fe − B nanocrystalline magnets

Titov, I. (Corresponding author) ; Barbieri, M. ; Bender, P. ; Peral, I. ; Kohlbrecher, J. ; Saito, K. ; Pipich, V.FZJ* ; Yano, M. ; Michels, A.

2019
APS College Park, MD

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Please use a persistent id in citations: http://hdl.handle.net/2128/23220  doi:10.1103/PhysRevMaterials.3.084410

Abstract: Hot-deformed anisotropic Nd−Fe−B nanocrystalline magnets have been subjected to the grain-boundary diffusion process (GBDP) using a Pr70Cu30 eutectic alloy. The resulting grain microstructure, consisting of shape-anisotropic Nd−Fe−B nanocrystals surrounded by a Pr−Cu-rich intergranular grain-boundary phase, has been investigated using unpolarized small-angle neutron scattering and very small-angle neutron scattering. The neutron data have been analyzed using the generalized Guinier-Porod model and by computing, model independently, the distance distribution function. We find that the GBDP results in a change of the geometry of the scattering particles: In the small-q regime, the scattering from the as-prepared sample exhibits a slope of about 2, which is characteristic for the scattering from two-dimensional platelet-shaped objects, while the GBDP sample manifests a slope of about 1, which is the scattering signature of one-dimensional elongated objects. The evolution of the Porod exponent indicates the smoothing of the grain surfaces due to the GBDP, which is accompanied by an increase of the coercivity.

Keyword(s): Magnetic Materials (1st) ; Magnetism (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Neutronenstreuung (JCNS-1)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. KWS-3: Very small angle scattering diffractometer with focusing mirror (NL3auS)

Appears in the scientific report 2019

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index Expanded ; Web of Science Core Collection

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