NMR Investigations of Spin Density Waves in Organic Metals and Vortices in Superconductors

有机金属中自旋密度波和超导体中涡流的核磁共振研究

• 批准号: 9705369
• 负责人: W. Gilbert Clark
• 金额: $ 24万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9705369&HistoricalAwards=false
• 关键词: NMR; Investigations; Spin; Density; Waves

w:\awards\awards96\num.doc 9705369 Clark This experimental research project employs techniques of nuclear magnetic resonance in study of the thermal and driven motions of the local broken symmetry ground state structures in CDW and SDW one-dimensional systems, and the motion of vortex structure in several Type-II superconductors. Organic metal systems for study include a Bechgaard salt alloy system and the blue bronze. Most of the experiments will employ pulsed NMR over a very wide range of frequencies and up to high pressures. In superconductors, recent NMR spin-echo field-rocking measurements will be extended to anisotropic superconductors to measure the anisotropy of the penetration depth; and to high field to measure the coherence length. Work is planned to extend the recent observations by NMR of rf-assisted flux-lattice annealing in anisotropic Type- II superconductors. Some very high magnetic field work will be performed at the National High Magnetic Field Laboratory. This study of unusual ground states in novel materials will extend the knowledge base and has potential to generate significant advances in basic solid state physics. It also will demonstrate new methods for using NMR which may be applicable in other circumstances. %%% This experimental research project uses primarily the technique of Nuclear Magnetic Resonance (NMR) to probe basic electrical properties of novel organic metal conductors, as well as aspects of the magnetic behavior in highly anisotropic superconductors. The organic conductors of interest exhibit nearly one-dimensional electrical conduction. Their electrical conduction is believed to occur by a novel mechanism known as a "sliding charge density wave", which involves a highly correlated motion of carriers, unlike conventional metals. The properties of this unusual effect, and materials that can exhibit it, a re of interest. Results from this research may include unusual new effects or materials which may find new application in technology. A portion of the work will be carried out at the National High Magnetic Field Laboratory. This research project is interdisciplinary in nature and involves both graduate and postgraduate students who will be excellently trained to enter positions in industry, government or education. ***

w:\awards\awards96\num.doc 9705369 Clark 该实验研究项目采用核磁共振技术研究 CDW 和 SDW 一维系统中局部破缺对称基态结构的热运动和驱动运动，以及运动几种II型超导体中的涡旋结构。用于研究的有机金属系统包括贝希加德盐合金系统和蓝青铜。 大多数实验将在很宽的频率范围和高达高压的范围内使用脉冲核磁共振。 在超导体中，最近的核磁共振自旋回波场摇摆测量将扩展到各向异性超导体，以测量穿透深度的各向异性； 并到高场测量相干长度。计划开展工作以扩展核磁共振对各向异性 II 型超导体中射频辅助通量晶格退火的最新观察结果。 一些极高磁场的工作将在国家强磁场实验室进行。 这项对新型材料中异常基态的研究将扩展知识基础，并有可能在基础固体物理学方面产生重大进展。它还将演示使用 NMR 的新方法，这些方法可能适用于其他情况。 %%% 该实验研究项目主要利用核磁共振（NMR）技术来探测新型有机金属导体的基本电特性，以及高度各向异性超导体的磁行为方面。 感兴趣的有机导体表现出近一维的导电性。人们认为它们的导电是通过一种称为“滑动电荷密度波”的新颖机制发生的，与传统金属不同，该机制涉及载流子的高度相关运动。 这种不寻常效应的特性以及能够表现出这种效应的材料引起了人们的兴趣。 这项研究的结果可能包括不寻常的新效应或可能在技术中找到新应用的材料。部分工作将在国家强磁场实验室进行。该研究项目本质上是跨学科的，涉及本科生和研究生，他们将接受良好的培训，以进入工业、政府或教育部门。 ***