Control of Ferromagnetic Resonance in Thin Films through Nanostructuring and Interfacial Torques

Ferromagnetic resonance and associated spin wave resonant excitations are studied in two different contexts. In the first context, magnetic excitations are studied in magnetic thin films that have periodic perturbations produced by by patterning nanostructured hole arrays on, or within the magnetic thin film, or by depositing a magnetic thin film on a colloidal crystal. In either scenario, it is found that the ferromagnetic resonant excitations can be modified by the imprinted periodicities.;The second area of study focuses on new ways to drive ferromagnetic thin films into resonance through interfacial spin-transfer-torque. The interfacial torque studied here is from the spin Hall effect. The films are magnetized in an arbitrary orientation both within and out of the plane of the film. By studying the ferromagnetic resonance in arbitrarily magnetized states it is found that the interfacial torques may have unexpected field-angular dependencies. This work also develops a simple model based on previously existing ideas to understand the out-of-plane angular dependence of ferromagnetic resonance driven by spin Hall effects.