Experimental Studies of Thin Film Magnetism

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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.