Applications of Neutron Scattering Techniques to the Investigation of Prototypical Magnetic Systems

中子散射技术在原型磁系统研究中的应用

• 批准号: 9302380
• 负责人: Jeffrey Lynn
• 金额: $ 37.5万
• 依托单位: University of Maryland, College Park
• 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: 1993-07-01 至 1997-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9302380&HistoricalAwards=false
• 关键词: Applications; Neutron; Scattering; Techniques; Investigation

This project will explore three general avenuew of research using both polarized and unpolarized neutron scattering techniques. The first involves the magnetic ordering and spin fluctuations associated with copper and rare earth moments in the oxide superconductors. the second concerns the superconducting aspects of these systems, including the investigation of the nature of the vortex state in these 'magnetic-superconductor' materials, as well as the determination of the magnetic penetration depth in superconductors via polarized neutron reflectometry. The third project deals with the spin dynamics of isotropic ferromagnets. Polarized beam techniques will be used to separate the longitudinal and transverse spin dynamics of materials, such as Invar alloys where substantial discrepencies have been found between the magnetic excitation spectrum observed directly with neutrons and the temperature dependence of the magnetization. Investigation of the longitudinal and transverse fluctuation spectra just below the Curie temperature, and their behavior as a function of applied field will be undertaken. %%% This project will explore three general avenues of materials research using neutron scattering techniques. The first involves the fundamental structural and magnetic properties of the cuprate superconductors, in an effort to establish the origins of the superconducting state in these novel systems. The second aspect concerns the determination and understanding of the materials properties which control the superconducting parameters of central importance to commercial applications, such as vortex pinning to produce high critical current materials. The final area deals with the fundamental and practical properties of soft magnetic materials, which have commercial applications as transformer cores, magnetic shielding, etc. Particular emphasis will be placed on the Invar class of soft magnets, as these are of technical importance because their density does not change with temperature, in contrast to most metals which expand upon heating.

该项目将探索三种研究的一般途径， 极化和非极化中子散射技术。 的 首先涉及到磁有序和自旋涨落 与氧化物中的铜和稀土元素有关 超导体 第二个是关于超导方面 这些系统，包括调查的性质， 这些“磁性超导体”材料中的涡旋状态， 作为确定磁穿透深度的方法， 通过极化中子反射仪测量超导体。 第三 该项目研究各向同性铁磁体的自旋动力学。 偏振光束技术将用于分离纵向 以及因瓦合金等材料的横向自旋动力学 其中发现， 直接用中子观测到的磁激发谱， 磁化强度的温度依赖性。 调查 纵向和横向波动谱正好低于 居里温度，以及它们的行为作为应用的函数 外地将进行。 %%% 这个项目将探索三种材料的一般途径 利用中子散射技术进行研究。 第一个涉及 铜氧化物的基本结构和磁性 超导体，在努力建立的起源， 在这些新系统中的超导状态。 第二方面 涉及材料的确定和理解 控制中心超导参数的性质 重要的商业应用，如涡流钉扎， 生产高临界电流材料。 最后一个领域涉及 软磁材料的基本特性和实用特性 材料，其具有作为Transformer芯的商业应用， 磁屏蔽等。特别强调将放在 因瓦类软磁铁，因为这些都是技术上的重要性 因为它们的密度不随温度变化， 大多数金属在加热时会膨胀。