FORMATION AND MAGNETIC PROPERTIES OF A NOVEL Gd3(Fe,Ti)29Ny NITRIDE

The novel Gd₃(Fe_0.978Ti_0.022)₂₉ compounds and their nitride have been synthesized. The X-ray diffraction patterns of the Gd₃(Fe,Ti)₂₉N_y and its parent compounds were indexed in the Nd₃(Fe,Ti)₂₉-type structure with a monoclinic symmetry and space group P2₁/c, Both the nitride and the parent compounds exhibit ferrimagnetlc coupling. Nitrogenatio led to an increase in Curie temperature and saturation magnetization. The Curie temperatures are 517K for the parent and 765K for the nitride. The saturation magnetizations σ_s at 4.2K are 101.9A·m²/kg for the parent and 128A·m²/kg for the nitride. Both the nitride and parent exhibit a planar anisotropy. Nitrogenation led to a decrease of the contribution of Fe-sublattice to planar anisotropy. The anisotropy fields at 4.2K are 9.8T for the parent and 6.5 T for the nitride.     

β-Ni3Nb相单个平移畴界的相干电子微衍射研究

本文采用ＨＦ－２０００ＦＥＧ电镜对Ｚｈａｎｇ等＾「７」已经用ＨＲ－ＴＥＭ高分辨技术研究的β－Ｎｉ３Ｎｂ相的几种单个平移畴界进行了相干电子微衍射研究,不但对已发现Ｒ１＝「１／２,０,０」和Ｒ２＝１／４「１０２」型平移畴界进行了微衍射分析,而且发现了Ｒ５＝「１／４,１／２,０．８１」型平移畴界。     

FORMATION AND MAGNETIC PROPERTIES OF A NOVEL Gd3(Fe,Ti)29Ny NITRIDE

The novel Gd₃(Fe_0.978Ti_0.022)₂₉ compounds and their nitride have been synthesized. The X-ray diffraction patterns of the Gd₃(Fe,Ti)₂₉N_y and its parent compounds were indexed in the Nd₃(Fe,Ti)₂₉-type structure with a monoclinic symmetry and space group P2₁/c, Both the nitride and the parent compounds exhibit ferrimagnetlc coupling. Nitrogenatio led to an increase in Curie temperature and saturation magnetization. The Curie temperatures are 517K for the parent and 765K for the nitride. The saturation magnetizations σ_s at 4.2K are 101.9A·m²/kg for the parent and 128A·m²/kg for the nitride. Both the nitride and parent exhibit a planar anisotropy. Nitrogenation led to a decrease of the contribution of Fe-sublattice to planar anisotropy. The anisotropy fields at 4.2K are 9.8T for the parent and 6.5 T for the nitride.     

纳米YBCO颗粒的团聚的TEM研究

纳米超导颗粒ＹＢａ2 Ｃｕ3 Ｏ7 ｘ是制备第二代高温超导带材非常有用的原料。我们研究的纳米超导颗粒ＹＢａ2 Ｃｕ3 Ｏ7 ｘ是采用柠檬酸盐热解法制备的[1] 。这种方法不同于传统制备大块样品的粉末冶金法 ,可以制备非常细小的颗粒。超导颗粒的颗粒度对纳米带材涂层的质量 ,以及颗粒结晶度的情况对Ｔｃ和Ｊｃ具有重要影响。自ＹＢａ2 Ｃｕ3 Ｏ7 ｘ 的高分辨结构像被ＨｉｒａｇａＫ[2 ] 得到以来 ,对超导材料的ＴＥＭ研究集中在大块材料和薄膜材料[3 ] ,只有非常少的工作报道了纳米ＹＢＣＯ颗粒的ＴＥＭ研究[4] 。本文将对氧气氛退火的纳米Ｙ…