Advanced Functional Materials
© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Editor-in-Chief: Joern Ritterbusch, Deputy Editors: Mary De Vita, Yan Li
Online ISSN: 1616-3028
Associated Title(s): Advanced Electronic Materials, Advanced Energy Materials, Advanced Engineering Materials, Advanced Healthcare Materials, Advanced Materials, Advanced Materials Interfaces, Advanced Materials Technologies, Advanced Optical Materials, Advanced Science, Particle & Particle Systems Characterization, Small
Circular Nanomagnets: Enhanced Nucleation of Vortices in Soft Magnetic Materials Prepared by Silica Nanosphere Lithography (Adv. Funct. Mater. 5/2011)
Magnetic vortices show promise as data storage structures, however the vortex formation process imposes a lower limit on the element’s size. In this article a technique is presented, which application increases the probability of nucleating of magnetic vortices in sub-micrometer sized soft magnetic thin film elements. By tailoring the edge geometry of the elements, the symmetry of their magnetic configuration is broken in a manner which favors vortex nucleation. Micromagnetic simulations are presented, which demonstrate this effect in soft-magnetic disks with beveled edges. The favored edge geometry is realized by applying nanosphere lithography directly on top of a ferromagnetic thin film material. In this process, the film is masked with a self assembled monolayer of SiO2-nanospheres and subsequently ion-etched. The resulting magnetic reversal loops show that in both magnetically isolated as well as in closely packed arrays of beveled disks, vortex formation takes place. The technique presented facilitates the vortex formation even in closely packed and small elements. The lowering of the minimum critical diameter for vortex formation enables a significant increase of data storage density in devices based on magnetic vortices.