LUO Yang JI Qigen ZHANG Ning SU Xiujin Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
ChinaSUN Daliang Shandong University
,
Jinan
,
China senior engineer
,
Department of Precious Alloys
,
Central Iron and Steel Research Institute
,
Beijing
,
China
金属学报(英文版)
Based on the observation of temperature variation of both domain structure and magnetic con- trast.the thermal demagnetization and randomness of domain nucleation was discussed.
关键词:
domain structure
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null
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null
,
null
王瑞坤
,
孙丽虹
,
李东培
,
应启明
,
竹山太郎
金属学报
在热退磁状态,这种永磁体的基体晶粒一般为多畴结构,单个畴为180°片状畴,也有少量钉形畴和迷宫畴。测得平均畴宽为1.5μm。还观察到一些直径1μm左右的单畴晶粒和极个别直径3μm左右的单畴晶粒,计算出畴壁能γ=36mJ/m~2,交换常数A=4.5×10~(-11)J/m,畴壁厚度δ=15.7nm,临界单畴晶粒直径D_c=0.5μm。还讨论了晶界附近存在高磁场梯度与晶界两侧相邻磁畴内磁化方向的关系和微观组织对K,A和δ值的影响。
关键词:
Nd-Fe-B永磁体
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domain structure
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magnetic property
王茂华
,
许小勇
,
胡经国
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2009.06.001
采用Monte Carlo模拟方法,通过反铁磁层中非磁性掺杂方式调节铁磁层与反铁磁层界面微结构,讨论了其界面微结构对体系的磁滞回线的不对称性、交换偏置场及矫顽场的影响.模拟结果显示:在同一掺杂浓度下,体系的磁滞回线的不对称性及交换偏置场强烈地依赖于掺杂方式,但矫顽场几乎不受影响,其相应的温度特性亦依赖于掺杂方式.它表明铁磁/反铁磁双层膜体系中的磁滞回线的不对称性以及交换偏置场与其界面微结构密切相关,同时实验上人们可通过界面微结构的改变获得交换偏置场大、矫顽场小且热稳定性好的自旋阀结构.
关键词:
铁磁/反铁磁双层膜
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交换偏置场
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矫顽场
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磁畴结构
王倩
,
王燕波
,
李扬
,
李培佳
,
张鑫
,
李俊涛
稀有金属
doi:10.3969/j.issn.0258-7076.2013.06.008
采用粉末冶金的方法制得2∶17型SmCo永磁体,通过对磁体进行X射线衍射(XRD)、振动样品磁强计(VSM)和磁力显微镜(MFM)等分析,较为系统地研究了Cu含量对Sm(Coba1Fe0.20CuxZr0.03)7.5(x=0.06,0.08)永磁体的磁畴结构及矫顽力的影响.研究结果表明,2∶17型SmCo永磁体属于多磁畴晶体,其磁畴结构主要表现为波纹畴结构,磁畴宽度约1～2 μm,畴宽远小于晶粒尺寸.Cu含量对磁体的X射线衍射谱没有明显影响,但对磁畴宽度和内禀矫顽力iHc影响很大,且磁畴宽度与内禀矫顽力iHc具有一定的对应关系.磁体的X射线衍射谱上显示了2∶17相和1∶5相特征峰,没有出现会影响磁体磁性能相的特征峰.Cu含量增大,X射线衍射谱并未出现明显的变化.随Cu含量增加,磁体磁畴宽度由2μm减小到1μm,1∶5胞壁相的畴壁能降低,内禀矫顽力iHc相应增大,表明畴壁钉扎是吸引型钉扎.内禀矫顽力iHc在室温时为2473 kA·m-1,到450℃时减小为457 kA·m-1,热激活能是内禀矫顽力iHc随温度升高而逐渐降低的主要因素.高温下Cu含量越高的磁体的2∶17主相和1∶5胞壁相间畴壁能差越大,从而使矫顽力随温度的升高衰减减缓.
关键词:
SmCo永磁材料
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磁畴结构
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矫顽力
,
磁性能
WANG Ruikun SUN Lihong LI Dongpei YING Qiming T.Takeyama General Research Institute for Non-Ferrous Metals
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Beijing
,
China [Originally published in ACTA METALL SIN (CHINESE EDN) 24 (5) 1988 pp B353—B358
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received 6 May 1987
,
in revised form 6 February 1988] T.Takeyama is an emeritus professor of HOKKAIDO University
,
Japan
,
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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null
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null
倪友保
,
吴海信
,
耿磊
,
王振友
,
毛明生
,
程干超
,
黄飞
人工晶体学报
利用本实验室生长的红外非线性晶体材料AgGaGeS_4(AGGS),常温下进行腐蚀实验并观察畴结构,测试了不同频率、电压下晶体的电滞回线以及同一电压下不同频率介质的电容值.腐蚀图像显示出畴结构,畴尺寸5～10 μm左右,证实AGGS为一热释电晶体.然而,室温下的电滞回线变形为一近似椭圆,介质电容与电场频率关系表现出强色散特性.本文对这一现象进行了系统分析,最后提出了进一步探索AGGS铁电性质的具体建议.
关键词:
AGGS晶体
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介电性能
,
畴结构
