Transition-Metal and Rare-Earth Systems: Magnetism and Structure

过渡金属和稀土系统：磁性和结构

• 批准号: 8722880
• 负责人: James Kouvel
• 金额: $ 1.89万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-15 至 1990-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8722880&HistoricalAwards=false
• 关键词: Transition; Metal; Rare; Earth; Systems

Magnetization-vector measurements are proposed for the detailed investigation of rotational magnetic processes in various spin- glass alloy systems (e.g. Copper-Manganese, Gold-Iron), including the onset of irreversibility arising from dissipative rotations of the anisotropy (initially produced by field-cooling) relative to the disordered crystal lattice. The lattice instability of the cubic phase of Yttrium-Copper (indicated by anomalous quadrupolar interactions in Holmium1-xYttriumxCopper of high x) will be probed by inelastic neutron scattering experiments. A binding-potential model for the structural instability of cubic Praseodymium-Silver1-xCopperx will be tested against neutron diffraction data on the orthorhombic compounds of high x. A series of Lanthanum2-xNeodymiumxCopper Oxide4 compounds spanning the composition for the tetragonal-orthorhombic transition will be studied magnetically for quadrupolar-coupling evidence of a lattice instability. Magnetization, specific heat, and resistivity measurements, supplemented by neutron diffraction work, will be performed on Terbium1-xYttriumxSilver and Gadolinium1-xYttriumxSilver in a study of the percolation- breakdown of the long-range antiferromagnetism with increasing x.

磁化矢量测量被提议用于详细研究各种自旋玻璃合金系统（例如铜-锰、金-铁）中的旋转磁性过程，包括相对于无序晶格的各向异性（最初由场冷却产生）的耗散旋转引起的不可逆性的开始。 钇-铜立方相的晶格不稳定性（由高 x 的钬1-x钇x铜中的反常四极相互作用表明）将通过非弹性中子散射实验来探测。 立方镨-银1-x铜的结构不稳定性的结合势模型将根据高 x 斜方化合物的中子衍射数据进行测试。 一系列涵盖四方-正交相变组成的 Lanthanum2-xNeodymiumxCopper Oxide4 化合物将通过磁性研究，以获取晶格不稳定性的四极耦合证据。 磁化强度、比热和电阻率测量，辅以中子衍射工作，将在铽 1-xYttriumx 银和钆 1-xYttriumx 银上进行，研究随着 x 的增加，长程反铁磁性的渗透分解。