Exchange anisotropy in Fe-Nd-B magnets

Journal Article · Mon Jan 01 04:00:00 EST 1990 · IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (USA)

DOI:https://doi.org/10.1109/20.50548· OSTI ID:6884438

Fukuno, A ^[1]; O'Handley, R C ^[2]

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1. TDK Corp., Research and Development Center, 15-7 Higashi-Owada, 2-chome, Ichikawa, Chiba (JP)
2. Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering

Large exchange anisotropy (1.0 to 1.5 kOe) has been observed by magnetooptic Kerr effect (MOKE) at the surface of Fe-Nd-B sintered magnets. Three samples Fe{sub 79 {minus} {ital x}}Nd{sub 13 + {ital x}}B{sub 8} with {ital x} = 0, 1, and 2 atom %, were studied. These materials showed bulk intrinsic coercivities of 0.3, 4.2, and 7.7 kOe respectively. All samples showed MOKE coercivities below 0.6 kOe. Only the {ital x} = 1 sample exhibited significant MOKE exchange anisotropy. A three-layer model is assumed near the surface: outermost, nonmagnetic Nd{sub 2}O{sub 3}, soft Fe-rich subsurface layer, and magnetically hard Fe{sub 14}Nd{sub 2}B bulk. The authors speculate that the bulk is exchange-coupled to the soft Fe-rich layer in the {ital x} = 0, 1 samples but not in the {ital x} = 2 sample because of the greater Nd content of the grain boundaries for {ital x} = 2. This explains both the low bulk coercivity in {ital x} = 0 and {ital x} = 1 and the observation of exchange anisotropy for {ital x} = 1 but not for {ital x} = 2.

• OSTI ID: 6884438
• Journal Information: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (USA), Journal Name: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (USA) Vol. 26:1; ISSN IEMGA; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360104* -- Metals & Alloys-- Physical Properties
640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
656100 -- Condensed Matter Physics-- Superconductivity
74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ANISOTROPY
BORON ALLOYS
COERCIVE FORCE
CRYSTAL STRUCTURE
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTRON-HOLE COUPLING
ELEMENTS
FABRICATION
GRAIN BOUNDARIES
IRON
IRON ALLOYS
KERR EFFECT
LAYERS
MAGNETIC PROPERTIES
MAGNETO-OPTICAL EFFECTS
MAGNETS
METALS
MICROSTRUCTURE
NEODYMIUM ALLOYS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SINTERING
TRANSITION ELEMENTS