The compounds RENi(BN) with RE = Y, La, Ce, Pr, Tm and Yb were synthesized by solid state reactions from metal powders and α-BN at temperatures between 1000° and 1200 °C. In addition, the mixed phases (Ca,Yb)Ni(BN) and (Ca,Tm)Ni(BN) were synthesized. All products were characterized by powder XRD measurements and indexed isotypic with the structure of CaNi(BN), consistent with the tetragonal space group
Neutron diffraction study of superconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mrow><mml:msub><mml:mrow><mml:mtext>La</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mtext>Ni</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mmultiscripts><mml:mtext>B</mml:mtext><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>N</mml:mtext><mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>
Abstract We have studied structural properties of La 3 Ni 2 B 2 N 3− δ samples with distinctly different values of the superconducting transition temperature by means of powder neutron diffractometry and specific heat measurements. The refinement of lattice site occupations reveals full occupations for all sites in the La 3 Ni 2 B 11 2 N 3 structure with space group I 4/ mmm except for nitrogen site
摘要 我们通过粉末中子衍射和比热测量研究了具有明显不同超导转变温度值的 La 3 Ni 2 B 2 N 3− δ 样品的结构特性。晶格位点占据的细化揭示了空间群I 4/ mmm La 3 Ni 2 B 11 2 N 3 结构中所有位点的完全占据,除了氮位点N(2)。对于 T c = 13.0 K 和 13.7 K 的样本,我们分别获得了 N(2) 站点明显不同的占用因子 0.90 和 0.93。后者证实了氮化学计量与超导转变温度之间的直接关系。基于对温度相关晶格参数、原子位移因子的分析,
Crystal Structure of Ce3Ni2(BN)2N and Magnetic Behavior of (CeNi(BN))2(CeN)x with x = 0, 1
作者:Jochen Glaser、Takao Mori、H.-Jürgen Meyer
DOI:10.1002/zaac.200800009
日期:2008.6
compound Ce3Ni2(BN)2N was synthesized by a modified solid state metathesis reaction. The crystalstructure of Ce3Ni2(BN)2N was found to be isotypic with the superconducting compound La3Ni2(BN)2N, according to Rietveld refinements performed on X-ray powder data (I4/mmm, Z = 2, a = 3.5817(1) A, c = 20.283(1) A). Corresponding solid state reactions of mixtures composed of CeN/NiB and CeNi/BN yielded CeNi(BN)
通过改进的固态复分解反应合成了新化合物Ce3Ni2(BN)2N。根据对 X 射线粉末数据 (I4/mmm, Z = 2, a = 3.5817(1)) 进行的 Rietveld 细化,发现 Ce3Ni2(BN)2N 的晶体结构与超导化合物 La3Ni2(BN)2N 同型A,c = 20.283(1) A)。由 CeN/NiB 和 CeNi/BN 组成的混合物的相应固态反应产生了 CeNi(BN) 和两种密切相关的层状结构 (CeNi(BN))2(CeN)x 的混合物,x = 0 和 1。 磁化实验在这些样品上显示了 Ce3Ni2(BN)2N 和 CeNi(BN) 的温度独立顺磁行为,没有任何低至 5 K 的磁性排序。
Surface characterisation of nickel boride and nickel phosphide catalysts by X-ray photoelectron spectroscopy
The surfacecharacterisation of nickelboride (NiB) and nickelphosphide (NiP) catalysts has been undertaken with X.p.s. Boron combined with nickel metal in NiB catalysts was found to donate electrons to the nickel metal, resulting in electron rich metal, whereas phosphorus bonded to nickel metal in NiP catalysts accepted electrons from the nickel metal, causing electron deficient metal. Preparation
作者:Anup Mondal、Sabyashachi Nath、Ashok Mondal、Sikha Bandopadhyay、Utpal Gangopadhyay、Hiranmay Saha
DOI:10.1002/pssa.200420042
日期:2005.7
Electroless deposition of Ni–B films on n-silicon has been developed, usingsodiumborohydride as the reducingagent. The deposition has been studied by varying the temperature, time of deposition and the concentration of the reducingagentused, keeping the pH of the solution unchanged. Sheet resistance of the deposited films were measured to confirm the growth. Preliminary studies on contact resistance