They plan to use the understanding gained of orbitally-driven anisotropic magnetic phenomena to elucidate and further advance the state of the giant magneto-optic effects discovered during the past few years in exactly the class of cerium and light actinide materials that they have been studying. In addition, they want to extend their present ab initio theory for orbitally- driven magnetism to uranium, manganese, and possibly some iron, systems. The extension to uranium, manganese, and iron is both of general interest, and of specific interest for exploring and exploiting giant magneto-optic effects. By orbitally-driven magnetism, they mean magnetic behavior where the interionic coupling is between orbital moments, rather than spin moments, on the interacting ions; and where this coupling is brought about by hybridization between moderately delocalized f-electrons and band electrons of non-f atomic parentage. In such a situation, they anticipate very large magneto-optic effects because there is no dependence on the spin-orbit coupling to provide a weak linkage between the optically active and the magnetically active components of the electronic system. Besides being of great basic scientific interest, the study of materials with very large magneto-optic effects is technologically of importance in order to find improved materials for use in large-scale erasable computer memories. The proposed research includes the theoretical component of a coordinated theoretical and experimental study of material properties to gain giant magneto- optic effects, with the experimental work being carried out by Dr. Mark H. Kryder of Carnegie-Mellon University and his group.
