Coercivity and spin reorientation transitions in Nd-Fe-B nanocomposites prepared by melt spinning

Journal Article · Thu May 01 04:00:00 EDT 1997 · IEEE Transactions on Magnetics

DOI:https://doi.org/10.1109/20.573858· OSTI ID:509275

Dahlgren, M; Kou, X C; Groessinger, R ^[1]; Liu, J F; Ahmad, I; Davies, H A ^[2]; Yamada, Koji ^[3]

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1. Vienna Univ. of Technology (Austria). Inst. for Experimental Physics
2. Univ. of Sheffield (United Kingdom). Dept. of Engineering Materials
3. Saitama Univ., Urawa (Japan). Dept. of Material Sciences

Alloys of composition Nd{sub 9}Fe{sub 85}B{sub 6}, Nd{sub 11.76}Fe{sub 82.46}B{sub 5.88}, and Nd{sub 18}Fe{sub 76}B{sub 6} were prepared by melt spinning at roll velocities from 19 to 25 m/s. The grain size distribution of rapidly quenched flakes were evaluated by means of X-ray diffraction line broadening. The average grain size of rapidly quenched Nd-Fe-B alloys is within a range from 19 to 40 nanometers and differs from the roll contact side to the free side of the flakes. For the first time, the spin reorientation transitions T{sub sr} of nanophase Nd{sub 2}Fe{sub 14}B alloys have been determined. They were found to be lower than that of bulk Nd{sub 2}Fe{sub 14}B. The smaller the grain size, the lower is T{sub sr}. Also for the first time, the temperature dependence of the coercivity of nanophase Nd-Fe-B magnets was determined from 4.2 to 300 K by measuring hysteresis loops on a single flake in a pulsed-field magnetometer with a field strength up to 24 MA/m. The coercivity of the nanophase Nd-Fe-B has less of a temperature dependence than sintered magnets.

• Sponsoring Organization: Fonds zur Foerderung der Wissenschaftlichen Forschung, Wien (Austria)
• OSTI ID: 509275
• Journal Information: IEEE Transactions on Magnetics, Journal Name: IEEE Transactions on Magnetics Journal Issue: 3 Vol. 33; ISSN IEMGAQ; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
COERCIVE FORCE
GRAIN SIZE
IRON BASE ALLOYS
MAGNETIC PROPERTIES
NEODYMIUM ALLOYS
PERMANENT MAGNETS
TEMPERATURE DEPENDENCE