Magnetic properties of patterned ferromagnetic nanowires

Abstract

We performed micromagnetic modeling of nanostructured permalloy (Ni80Fe20) nanowires and showed that their magnetic switching and magnetotransport properties can be modified by the introduction of geometric features, such as side-elements and U-shaped castellations. Ferromagnetic side-elements, when placed adjacent to the nanowire, act as biasing elements, which oppose magnetic reversal in the nanowire and markedly increase its coercivity. Castellations, or kinks consisting of perpendicular segments, result in the nanowire exhibiting a combination of easy and hard-axis response to the applied field along its length, which may be regarded as a geometrically-induced cubic-like anisotropy. The resulting complex MR behavior shows switching between several distinct states. The sharp reversals between these states may possibly be utilized for sensor applications. Copyright © 2007 American Scientific Publishers. All rights reserved.