Fabrication and Characterization of Ferromagnetic Nanorings
Ferromagnetic nanorings are model systems for the study of magnetic phenomena in thin film structures. Unique closed flux states with potential applications in memory storage have also been observed in nanorings. A comprehensive understanding of the stability and the switching mechanisms of these novel states is important for data storage applications. We fabricate nanorings through electron beam lithography (EBL) to study the in-plane evolution of magnetic states in ferromagnetic ring structures. A systematic field dependent study of the nanoring states is performed using magnetic force microscopy (MFM). Micromagnetic simulations are used to suggest approximate fabrication dimensions and to interpret MFM results. We also explore a new method to control the vortex chirality in nanorings using a current generated magnetic field. In this technique, a magnetic field created by an atomic force microscope (AFM) probe placed at the center of the ring is used to manipulate the vortex chirality. Initial steps to the implementation of this technique have been performed and preliminary results are presented.