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新型金属间化合物R_2Fe_(17)N_(2.4)的结构与磁性 总被引:2,自引:0,他引:2
本文采用适当的热处理,使氮原子进入到R_2Fe_(17)的结构中去.利用X射线衍射、磁测量和中子衍射技术研究了R_2Fe_(17)N_(24)的晶体结构和内禀磁性及其之间的联系.中子衍射研究结果表明,氮原子在Th_2Zn_(17)型菱方结构中,占据9e间隙位置.氮的加入使晶胞体积增大、Curie温度升高;使铁原子3d电子正负能带电子数目差额扩大、饱和磁矩增强;并且氮原子对稀土晶位的晶场效应有重大影响,导致Sm_2Fe_(17)N_(24)具有易磁化轴.所有这些效应使得Sm_2Fe_(17)N_(24)具备了研制高矫顽力永磁体的内禀性能. 相似文献
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新型镨-铁-钼系和铈-铁-钼系氮化物的结构和磁性 总被引:2,自引:0,他引:2
对于轻稀土,特别是铈和镨,难以形成具有ThMn_(12)型结构的釜属间化合物,本文通过适当的热处理,制备成功单相的CeMo_(1.5)Fe_(10.5)和PrMo_(1.5)Fe_(10.5)及其氮化物,特别是PrMo_(1.5)Fe_(10.5)N_x,c轴为易磁化方向,并具有高居里温度、高各向异性场和高饱和磁化强度,可开发为有应用价值的新型磁体。 相似文献
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采用适当的热处理,使碳原子和氮原子先后进入到R_2Fe(17)的结构中去。利用X射线折射和磁测量技术研究了R_2Fe_(17)CN_x的晶体结构和内禀磁性。碳、氮的加入使晶胞体和膨胀、居里温度升高、饱和磁矩增大,并加强了稀土晶位的轴各向异性。 相似文献
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By a proper thermal treatment, the nitrogen atoms can enter the R2Fe17 structure. The crystallographic and intrinsic magnetic properties as well as their relationship have been studied by magnetic measurements, X-ray and neutron diffraction techniques. The neutron data indicate that the nitrogen atoms occupy the interstitial sites in the Th2Zn17-type rhom-bohedral structure. The inserting nitrogen atoms are found to dilate the cell volume, increase the Curie temperature and enhance the saturation moment by raising the difference in the electron number between the spin-up and spin-down 3d subbands of the Fe atoms. Furthermore, the nitrogen atoms have an important effect on the magnetocrystallic anisotropy, which results in an easy axis with Sm2Fe17N2.4. All these make Sm2Fe17N2.4 favorable for permanent magnet applications. 相似文献
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We found that the nitrogen atoms can enter into the R2Fe14B structure by a proper heat treatment in nitrogen atmosphere. The crystallographic structure and magnetic properties of R2Fe14BNx, R =Nd and Y, have been investigated by using X-ray and neutron diffraction techniques as well as magnetic measurements. The neutron diffrac-tion data show that the nitrogen atoms occupy the 4f interstices. The interstitial nitrogen atoms were found to have an effect of enhancing Curie temerature, whereas, decreasing saturation magnetization and magneto-crystalline anisotropy. The rela-tionship of the crystal structure and the intrinsic magnetic properties of this crystal is discussed. 相似文献
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We found that the nitrogen atoms can enter into the R2Fe14B structure by a proper heat treatment in nitrogen atmosphere. The crystallographic structure and magnetic properties of R2Fe14BNx, R =Nd and Y, have been investigated by using X-ray and neutron diffraction techniques as well as magnetic measurements. The neutron diffrac-tion data show that the nitrogen atoms occupy the 4f interstices. The interstitial nitrogen atoms were found to have an effect of enhancing Curie temerature, whereas, decreasing saturation magnetization and magneto-crystalline anisotropy. The rela-tionship of the crystal structure and the intrinsic magnetic properties of this crystal is discussed. 相似文献
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MAGNETIC PROPERTIES OF NEW SERIES R-Mo-Fe NITRIDES WITH THE ThMn12-TYPE STRUCTURE AT A LOWER Mo CONTENT 下载免费PDF全文
A systematic study has been made on formation condition, crystallographic structure and magnetic properties of RMo1.5Fe10.5Nx, where R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er. The interstitial nitrogen atom effects on Curie temperature, saturation magnetization and magneto-crystalline anisotropy have been investigated. Two important preliminary results have been obtained. (1) A single phase crystallized in the ThMn12-type structure was stabilized with a smaller content of molybdenum, thus, the compounds possess a higher Curie temperature and a larger spontaneous magnetization. (2) A complete system of compounds with 1:12 type structure containing the light rare earth cerium and praseodymium was synthesized, which will be favorable for developing new rare earth hard magnetic materials. 相似文献
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网络研究已经成为机器学习领域中的热点问题之一,近年来发展起来的随机块模型是通过建模生成网络的一种方法.本文对随机块模型加以推广,建立加权的随机块模型,在求解过程中,采用一种可以广泛的用于求解混合模型的变分EM算法.最后通过数据模拟,证明了此方法的可行性. 相似文献