CeCu2Si2单晶生长、高能磁激发和整体磁谱研究

项目名称： CeCu2Si2单晶生长、高能磁激发和整体磁谱研究

项目编号： No.51471135

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 曹崇德

作者单位： 西北工业大学

项目金额： 84万元

中文摘要： 采用高压浮区技术进行CeCu2Si2重费米子化合物大体积单晶生长研究，确定形成CeCu2Si2单晶的热力学条件和成分范围，研究制备工艺参数和磁性过渡金属元素掺杂对晶体相形成、微观结构、成分分布、晶体缺陷等的影响规律，制备出CeCu2Si2和Ce(Cu1-xMx)2Si2高质量大单晶。研究Cu位掺杂磁性过渡金属元素对CeCu2Si2晶体结构、磁结构、离子价态和物理性能的影响。针对大单晶体采用中子散射飞行时间测量研究CeCu2Si2的磁结构、高能自旋激发和整体磁谱以及磁性过渡元素掺杂的影响，探索反铁磁和超导的相互作用关系，为揭示非常规超导的起源提供实验和理论依据。

中文关键词： 晶体生长；定向凝固；CeCu2Si2；中子散射；磁激发

英文摘要： Large single crystal growth of heavy fermion compound CeCu2Si2 will be investigated by using high pressure floating zone technique. The thermodynamics and composition ranges will be determined for A-, AS- and S-type CeCu2Si2, respectively. We will grow large single crystals of CeCu2Si2 with A, AS or S phases, with revealing the effect of parameters during high pressure floating zone growth on the phase constitution, structure, composition and defects of crystals.The effect of doping with magnetic transition metals on crystal structure, magnetic structure and physical properties of CeCu2Si2 will be studied and the intrinsic mechanism of composition difference resulting in A, S, and AS phases is expected to be demonstrated. With the large single crystals, neutron time-of -flight scattering will be carried out to explore the magnetic structures and high energy spin excitations for the A, AS and S type CeCu2Si2. And thus, we can map out the spin excitations in the whole zone and determine the overall magnetic spectral weight and effective magnetic exchange interaction. The interplay between antiferromagnetism and superconductivity is expected to be further demonstrated, leading to better understanding of the origin of unconventional superconductivity.

英文关键词： crystal growth;directional solidification;CeCu2Si2;neutron scattering;spin excitation