Effect of circular voids on the domain configuration of NI80FE20 micro-structures

Abstract

Magnetic patterned structures using soft materials like Ni80Fe20 are explored due to its applications in information storage. Different shapes such as squares and ellipses have been patterned and studied for their magnetic domain configuration and switching behavior. Defects in the structures have been found to serve as pinning centers for domain walls or vortices. The introduction of holes into the structures modifies their domain configurations and switching properties. In this work, we study the effect of circular voids in capsule-shaped 2 um x 1 um structures by varying the position, the number and the size of the holes and the structure's aspect ratio. Instead of using the conventional method of switching by using an external field, we use the circumferential field from a current-carrying conductor. Magnetic force microscopy (MFM) was used to image the domain configurations of the structure and results compared to simulation done using Object-oriented Micro-magnetic Framework (OOMMF).