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Spin Structures of Textured and Isotropic Nd-Fe-B-Based Nanocomposites: Evidence for Correlated Crystallographic and Spin Textures

A. Michels1,*, R. Weber1, I. Titov1, D. Mettus1, É. A. Périgo1,2, I. Peral1,3, O. Vallcorba4, J. Kohlbrecher5, K. Suzuki6 et al.

M. Ito7, A. Kato7, and M. Yano7

  • 1Physics and Materials Science Research Unit, University of Luxembourg, 162a avenue de la Faencerie, L-1511 Luxembourg, Luxembourg
  • 2ABB Corporate Research Center, 940 Main Campus Drive, Raleigh, North Carolina 27606, USA
  • 3Materials Research and Technology Department, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422 Belvaux, Luxembourg
  • 4Alba Synchrotron, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Barcelona, Spain
  • 5Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
  • 6Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
  • 7Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193, Japan

  • *andreas.michels@uni.lu
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Phys. Rev. Applied 7, 024009 – Published 9 February, 2017

DOI: https://doi.org/10.1103/PhysRevApplied.7.024009

Abstract

We report the results of a comparative study of the magnetic microstructure of textured and isotropic Nd2Fe14B/α−Fe nanocomposites using magnetometry, transmission electron microscopy, synchrotron x-ray diffraction, and, in particular, magnetic small-angle neutron scattering (SANS). Analysis of the magnetic neutron data of the textured specimen and computation of the correlation function of the spin-misalignment SANS cross section suggests the existence of inhomogeneously magnetized regions on an intraparticle nanometer length scale, about 40–50 nm in the remanent state. Possible origins for this spin disorder are discussed: it may originate in thin-grain-boundary layers (where the material parameters are different than in the Nd2Fe14B grains), or it may reflect the presence of crystal defects (introduced via hot pressing), or the dispersion in the orientation distribution of the magnetocrystalline anisotropy axes of the Nd2Fe14B grains. X-ray powder diffraction data reveal a crystallographic texture in the direction perpendicular to the pressing direction—a finding which might be related to the presence of a texture in the magnetization distribution, as inferred from the magnetic SANS data.

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Phys. Rev. Applied 7, 024009– Published 9 February, 2017
  • Received 1 September 2016

© 2017 American Physical Society

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