TY - JOUR
T1 - Magnetic domain structures of overquenched Nd-Fe-B permanent magnets studied by electron holography
AU - Park, Y. G.
AU - Shindo, D.
N1 - Funding Information:
The authors gratefully acknowledge Dr. H. Hiroyoshi, for providing them with the overquenched Nd 2 Fe 14 B samples. This work was partly supported by Special Coordination Funds for Promoting Science and Technology on “Nanohetero Metallic Materials” from the Science and Technology Agency.
PY - 2002/1
Y1 - 2002/1
N2 - Microstructures and magnetic domain structures of overquenched Nd-Fe-B permanent magnets have been investigated in detail by transmission electron microscopy. While magnetic domain boundaries are clarified by Lorentz microscopy, magnetization distribution in the domains is clearly observed by electron holography. In the as-quenched magnet, the size of the magnetic domains is in the range from 200 to 500nm and the direction of the magnetic lines of force changes gradually in wide region, while in the annealed one having the crystalline phase of Nd2Fe14B, the direction of the magnetic lines of force changes drastically especially at the grain boundaries. Furthermore, the direction of the magnetic lines of force changes more drastically in the specimen annealed at 893K than the specimen annealed at 843K. This result clearly indicates that the magnetocrystalline anisotropy is enhanced with the increase of annealing temperature, resulting in strong domain wall pinning.
AB - Microstructures and magnetic domain structures of overquenched Nd-Fe-B permanent magnets have been investigated in detail by transmission electron microscopy. While magnetic domain boundaries are clarified by Lorentz microscopy, magnetization distribution in the domains is clearly observed by electron holography. In the as-quenched magnet, the size of the magnetic domains is in the range from 200 to 500nm and the direction of the magnetic lines of force changes gradually in wide region, while in the annealed one having the crystalline phase of Nd2Fe14B, the direction of the magnetic lines of force changes drastically especially at the grain boundaries. Furthermore, the direction of the magnetic lines of force changes more drastically in the specimen annealed at 893K than the specimen annealed at 843K. This result clearly indicates that the magnetocrystalline anisotropy is enhanced with the increase of annealing temperature, resulting in strong domain wall pinning.
KW - Domain wall pinning
KW - Electron holography
KW - Magnetic flux density
KW - Magnetization distribution
KW - Reconstructed phase image
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U2 - 10.1016/S0304-8853(01)00699-0
DO - 10.1016/S0304-8853(01)00699-0
M3 - Article
AN - SCOPUS:0036132391
VL - 238
SP - 68
EP - 74
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
IS - 1
ER -