Low-Dimensional Quantum Antiferromagnets

低维量子反铁磁体

• 批准号: 9302065
• 负责人: Daniel Reich
• 金额: $ 15万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9302065&HistoricalAwards=false
• 关键词: Low; Dimensional; Quantum; Antiferromagnets

9302065 Reich A series of experiments are proposed to explore the ground state properties and excitations of low-dimensional antiferromagnetic materials that exhibit novel cooperative quantum effects. A zero- temperature phase transition will be explored by varying the parameters in the Hamiltonian of spin-1 chain through the application of pressure. A field-induced incommensurate soft mode in the spin-1/2 chain will be studied in detail. The properties of quantum systems with competing interactions will be examined through experiments on one-dimensional chains with next-nearest neighbor infractions and two-dimensional systems with geometrical frustration. The research will involve crystal growth and characterization, low-temperature thermodynamic measurements, and detailed studies of dynamical properties via inelastic neutron scattering. %%% This research involves the growth and characterization of materials which have magnetic properties largely constrained to occur along one- or two-dimensions. The magnetic properties become pronounced at low temperatures, and are also influenced by application of hydrostatic pressure. The research will provide fundamental information relevant to magnetism, and to the field of high-Tc superconducting materials. The materials will be investigated using magnetic measurements and by the technique of neutron scattering which reflects dynamical aspects of the atomic magnets in the various materials. ***

9302065赖希提出了一系列的实验来探索低维反铁磁材料的基态性质和激发，表现出新颖的合作量子效应。 通过施加压力改变自旋为1的链的哈密顿量中的参数，将探索零温相变。 我们将详细研究自旋为1/2的链中的场诱导无公度软模。 具有竞争相互作用的量子系统的性质将通过具有次近邻违反的一维链和具有几何挫折的二维系统的实验来检查。 研究将涉及晶体生长和表征，低温热力学测量，以及通过非弹性中子散射详细研究动力学性质。 这项研究涉及材料的生长和表征，这些材料的磁特性在很大程度上被限制在沿着一维或二维方向。 磁性在低温下变得明显，并且还受到流体静压力的影响。 这项研究将提供有关磁学和高温超导材料领域的基本信息。 这些材料将使用磁测量和中子散射技术进行研究，中子散射技术反映了各种材料中原子磁体的动力学方面。 ***