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Title: Direct observation of ferromagnetism in grain boundary phase of Nd-Fe-B sintered magnet using soft x-ray magnetic circular dichroism

We have investigated the magnetism of the grain boundary (GB) phase in a Nd{sub 14.0}Fe{sub 79.7}Cu{sub 0.1}B{sub 6.2} sintered magnet using soft x-ray magnetic circular dichroism (XMCD) at the Fe L{sub 2,3}-edges. Soft XMCD spectra were measured from the fractured surface that was confirmed to be covered with a thin GB phase by Auger electron spectroscopy. The magnetic moment of Fe in the GB phase was estimated to be m{sub GB}=1.4 μ{sub B} at 30 °C using the sum rule analysis for XMCD spectra, which is 60% of that of Fe in the Nd{sub 2}Fe{sub 14}B compound. The temperature dependence of m{sub GB} evaluated with reference to Fe in the Nd{sub 2}Fe{sub 14}B phase indicated that the Curie temperature of the GB phase is more than 50 °C lower compared to that of Nd{sub 2}Fe{sub 14}B.
Authors:
 [1] ;  [2] ; ;  [1] ; ;  [3] ;  [4] ; ; ; ;  [5] ;  [5] ;  [6]
  1. Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo 679-5198 (Japan)
  2. (ESICMM), National Institute for Materials Science, Tsukuba 305-0047 (Japan)
  3. Magnetic Materials Research Laboratory, Hitachi Metals, Ltd., 2-15-17 Egawa, Shimamoto 618-0013 (Japan)
  4. National Institute for Materials Science, Tsukuba 305-0047 (Japan)
  5. Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba 305-0047 (Japan)
  6. (Japan)
Publication Date:
OSTI Identifier:
22392020
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AUGER ELECTRON SPECTROSCOPY; BORON COMPLEXES; COPPER COMPLEXES; CURIE POINT; FERROMAGNETISM; GRAIN BOUNDARIES; IRON COMPLEXES; MAGNETIC CIRCULAR DICHROISM; MAGNETIC MOMENTS; MAGNETS; NEODYMIUM COMPLEXES; SINTERING; SOFT X RADIATION; SURFACES; TEMPERATURE DEPENDENCE