Conduction Electrons and Magnetism.

During the period of this grant, significant progress was made towards an understanding of the ferromagnetism of metals. Since some of the basic problems of ferromagnetism concern the analysis of the phase transition, the author first studied analogous systems which could be handled more readily, or for which experiments were more accessible. This progress involved several related lines of inquiry. These included an analysis of the low temperature damping of long wavelength spin waves, an analysis of the interaction of collective and single-particle excitations in the context of superconductivity, work on the formal theory of phase transitions in systems with a large number of spin degrees of freedom and work on the influence of surfaces and interfaces in phase transitions. Consideration of these various aspects of the problem has led us to a new approach to the theory of metallic ferromagnetism, which is now under active development. Modified author abstract