9701685 Sooryakumar This renewal project will support the study, via inelastic light scattering methods, of exchange coupling mechanisms across magnetic interfaces separated by an ultra thin spacer layer. Special tri-layer structures with the ability to tune the Stoner exchange parameter will allow details of the spacer magnetic and electronic structure that directly controls the inter-layer exchange to be probed and provide information on the antiferromagnetic properties of ultra thin metallic films. Domain wall excitations will also be exploited to study inter-layer coupling over microscopic length scales. In addition, the strong spin-lattice and charge-lattice couplings in the mixed valence manganites will be investigated by light scattering. This effort will allow for the unusual, but decidedly important, interplay between magnetic and structural effects in these materials to be studied. %%% This renewal project will support a laser spectroscopic study of magnetism in layered structures that are likely to underlie the next generation magnetic data storage and magneto-electronic devices. The study focuses on understanding the interaction between magnetic films separated by a few atomic layers and to develop an experimental technique to probe this interaction over length scales not realized by other methods. In addition, since the electrical resistance of special manganite compounds can be tuned by a magnetic field, these materials open new perspectives into novel devices based on the spin of an electron. The underlying physics associated with the coupling between the electron spin and crystal structure of these materials will be investigated by laser light scattering methodologies. ***
