Experimental Studies of Thin Film Magnetism

本项目研究薄膜结构、表面和界面所固有的物质的电子和磁性。这项提议的工作是由有意修改和表征影响磁性行为的物质的物理性质的新能力以及最近磁敏感光谱技术的改进所推动的。实验方法结合了新型材料合成、先进的结构测定方法和自旋敏感光谱技术。该计划的主要科学目标是探索原子水平结构与磁性之间的关系，并探索相变中的基本概念。提出的实验解决了影响超薄外延膜中磁各向异性、磁矫顽力和磁剩余力的原子水平因素以及通过超薄非磁性层的磁耦合。实验还解决了统计力学中的问题，包括二维普适性类的概念以及标度参数和临界指数的相关具体理论预测。这些重要的概念是在代表从二维到三维物质状态过渡的实验条件下研究的。薄膜和多层磁性材料为记录介质和新型高密度离散数字数据存储概念的未来发展提供了诱人的机会。这些材料也提供了重要的新的科学机会，以寻求更彻底地了解广泛的现象，说明磁性材料的商业重要性。薄膜磁性结构领域的机会尤其具有吸引力，因为新的加工技术和测量技术允许合成和表征具有选定特性的工程材料。本研究计划研究薄膜磁性行为的几个相关方面，这些方面与先进材料加工和薄膜材料的潜在应用有关。该计划的主要重点是了解材料加工（薄膜生长），薄膜结构（包括成分和原子水平效应）之间的关系，以及可以用于各种应用的磁性特性。

This project investigates electronic and magnetic properties of matter that are intrinsic to thin film structures, surfaces, and interfaces. The propsed work is driven by new capabilities to deliberately modify and characterize physical properties of matter that affect magnetic behavior, and by recent improvements in magnetically sensitive spectroscopic techniques. The experimental approach combines novel materials synthesis, advanced structure determination methods, and spin sensitive spectroscopic techniques. The principle scientific objectives of the program are to explore the relationship between atomic level structure and magnetism, and to probe fundamental concepts in phase transitions. Proposed experiments address atomic level factors that affect magnetic anisotropy, magnetic coercive forces, and magnetic remanence in ultra-thin epitaxial films and magnetic coupling through ultra-thin non-magnetic layers. The experiments also address issues in statistical mechanics including the notion of two-dimensional universality classes and related specific theoretical predictions of scaling parameters and critical exponents. These important concepts are studied under experimental conditions that represent a transition from the two-dimensional to three-dimensional state of matter. %%% Thin film and multilayer magnetic materials offer attractive opportunities for future development of recording media and of novel high-density discrete digital data storage concepts. These materials also offer important new scientific opportunities for seeking a more thorough understanding of the broad range of phenomena that account for the commercial importance of magnetic materials. The opportunities are especially attractive in the area of thin film magnetic structures because new processing technology and measurement techniques permit synthesis and characterization of engineered materials having selected characteristics. This research program investigates several related aspects of thin film magnetic behavior that are relevant to advanced materials processing and potential application of thin film materials. The principle emphasis of the program is to understand the relationship between the materials processing (film growth), the structure of the films including compositional and atomic level effects, and the resulting magnetic characteristics that can be exploited for various applications.