WANG Ruikun SUN Lihong LI Dongpei YING Qiming T.Takeyama General Research Institute for Non-Ferrous Metals
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Beijing
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China [Originally published in ACTA METALL SIN (CHINESE EDN) 24 (5) 1988 pp B353—B358
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received 6 May 1987
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in revised form 6 February 1988] T.Takeyama is an emeritus professor of HOKKAIDO University
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Japan
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and now is a technical adviser of GRINFM
金属学报(英文版)
The magnetic domain structure and related magnetic properties of (NdPr)_(16)Fe_(76)B_8 permanent magnet have been studied by colloid-SEM method.In thermally demagnetized state,the ma- trix grains in the magnet generally exhibit multidomain structure,i.e.,180° plate-like indi- vidual domain and a few spike-like or maze-like domains.The average width of the domain measured was 1.5μm.Grain size of single-domain was observed to be generally about 1μm and only a few up to 3μm.The results calculated are:the domain wall energy γ=36 MJ/m~2,the exchange constant A=4.5×10~(-11)J/m,the domain wall width δ=15.7nm, and the critical grain diameter of single-domain D_c=0.5μm.The dependence of high magnet- ic field gradient at grain boundaries in different magnetization directions in the adjacent mag- netic domains located on both sides of grain boundaries and the effect of microstructure on the values of K,A and δ were discussed.
关键词:
Nd-Fe-B permanent magnet
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