Neutron Scattering Techniques Applied to the Investigation of Prototypical Magnetic Systems

小林恩9701339 该项目将探索三种一般研究途径。 第一个涉及的磁阻氧化物的结构和动力学。 这项工作将 采用 极化和非极化中子散射技术来研究磁性和晶体结构，这两者之间的耦合性质，以及自旋和晶格动力学激发。 第二个领域涉及超导体中涡旋态的性质，当晶格变得 当稀土磁有序化时， 最后一个感兴趣的领域涉及各向同性铁磁物质的自旋动力学研究。 极化束技术将用于分离异常系统中材料的纵向和横向自旋动力学，如因瓦合金。 我们还将继续 我们 纵向调查 和横向 波动光谱 的 居里温度，以及它们作为外加场的函数的行为。 本计画将探讨三种利用中子散射技术进行材料研究的一般方法。 第一个涉及到巨大的磁阻氧化物的基本结构和磁性，在努力建立在这些金属绝缘体过渡的起源， 小说 系统. 第二个方面涉及 确定和理解控制超导参数的材料特性，这些参数对商业应用至关重要，例如生产高临界电流材料的涡旋钉扎。 最后一个领域涉及软磁材料的基本和实际性能，这些性能对于Transformer铁芯、磁屏蔽等具有重要的商业意义。 特别强调将放在因瓦类的软磁铁，因为这些是技术的重要性，因为他们的密度不 不随温度变化，与大多数金属受热膨胀相反。 ***

9701339 Lynn This project will explore three general avenues of research. The first involves the structure and dynamics of the magnetoresistive oxides. This work will employ both polarized and unpolarized neutron scattering techniques to study the magnetic and crystal structures, nature of the coupling between these two, and the sping and lattice dynamical excitations. The second area concerns the nature of the vortex state in superconductors, when the lattice becomes disordered, and when the rare earth magnetic ordering occurs. The final area of interest involves the study of the spin dynamics of isotropic ferromagnetics. Polarized beam techniques will be used to separate the longitudinal and transverse spin dynamics of materials in anomalous systems such as Invar alloys. We will also continue our investigations of the longitudinal and transverse fluctuation spectra just below the Curie temperature, and their behavior as a function of applied field. %%% 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 colossal magnetoresistive oxides, in an effort to establish the origins of the metal insulator transition in these novel systems. The second aspect concerns a determination and understanding of the materials properties which control the superconducting parameters of central importanceto commercial applications, such as vortex pinning to produce high critical current materials. The final area concerns the fundamental and practical properties of soft magnetic materials, which are of commercial importance for 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 chan ge with temperature, in contrast to most metals which expand upon heating. ***