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：\奖项\ Awards96 \ num.Doc 9705369 Clark该实验研究项目采用了核磁共振技术来研究CDW和SDW一维系统中局部破碎的对称地面状态结构的热和驱动动作，以及几种类型 - II超级辅助的运动中的运动。用于研究的有机金属系统包括Bechgaard盐合金系统和蓝色青铜。 大多数实验将在非常广泛的频率和高压范围内采用脉冲NMR。 在超导体中，最近的NMR自旋回波场循环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。 并到达高场以测量相干长度。计划通过NMR对各向异性型超导体的NMR进行NMR的最新观察结果。 一些非常高的磁场工作将在国家高磁场实验室进行。 这项对新型材料中异常基础状态的研究将扩展知识库，并具有在基本固态物理学方面产生重大进步的潜力。它还将展示使用NMR的新方法，该方法可能适用于其他情况。 %% %%该实验研究项目主要使用核磁共振（NMR）的技术来探测新型有机金属导体的基本电气，以及高度各向异性超导体中磁性行为的方面。 感兴趣的有机导体表现出近一维电导传导。人们认为它们的电导传导是通过一种称为“滑动电荷密度波”的新型机制发生的，该机制涉及载体高度相关的运动，这与常规金属不同。 这种异常效果的特性以及可以表现出的材料，一种感兴趣的材料。 这项研究的结果可能包括异常的新效果或可能在技术中找到新应用的材料。一部分工作将在国家高磁场实验室进行。该研究项目本质上是跨学科的，涉及研究生和研究生，他们将受到良好的培训，可以进入行业，政府或教育。 ***