GENERATION OF SPIN CURRENTS IN FERROMAGNETIC MATERIALS

Abstract

This thesis will discuss the utilization of ferromagnets for the generation of spin currents via various spin Hall like effects. The global magnetic order in a ferromagnetic material breaks the requisite symmetries to allow for the generation of spin currents with arbitrary polarizations which could prove useful for magnetic information storage technology. We first discuss some of the theoretical background of the various microscopic origins which can lead to spin Hall currents in ferromagnets as well as the theory behind some of the the experimental techniques used in this thesis. We then describe the measurement of a non-reorientable component of the spin Hall effect generated by a ferromagnetic Ni-Fe alloy using the spin torque ferromagnetic resonance technique, as well as modifications that we needed to make to the analysis of these measurements to account for coupling between magnetic layers driven by dynamic spin pumping. We conclude with a discussion of the materials problems which must be solved to utilize the spin anomalous Hall effect to switch out-of-plane polarized ferromagnetic layers as well as our attempts to realize such material systems.