Route to form skyrmions in soft magnetic films

Navas, D., Verba, R.V., Hierro-Rodriguez, A., Bunyaev, S.A., Zhou, X., Adeyeye, A.O., Dobrovolskiy, O.V., Ivanov, B.A., Guslienko, K.Y. and Kakazei, G.N. (2019) Route to form skyrmions in soft magnetic films. APL Materials, 7(8), 081114. (doi: 10.1063/1.5093371)

Abstract

Magnetic skyrmions which are topologically nontrivial magnetization configurations have attracted much attention recently due to their potential applications in information recording and signal processing. Conventionally, magnetic skyrmions are stabilized by chiral bulk or interfacial Dzyaloshinskii-Moriya interaction (DMI) in noncentrosymmetric B20 bulk crystals (at low temperatures) or ultrathin magnetic films with out-of-plane magnetic anisotropy (at room temperature), respectively. The skyrmion stability in the ultrathin films relies on a delicate balance of their material parameters that are hard to control experimentally. Here, we propose an alternate approach to stabilize a skyrmion in ferromagnetic media by modifying its surroundings in order to create strong dipolar fields of the radial symmetry. We demonstrate that artificial magnetic skyrmions can be stabilized even in a simple media such as a continuous soft ferromagnetic film, provided that it is coupled to a hard magnetic antidot matrix by exchange and dipolar interactions, without any DMI. Néel skyrmions, either isolated or arranged in a 2D array with a high packing density, can be stabilized using antidot as small as 40 nm in diameter for soft magnetic films made of Permalloy. When the antidot diameter is increased, the skyrmion configuration transforms into a curled one, becoming an intermediate between the Néel and Bloch skyrmions. In addition to skyrmions, the considered nanostructure supports the formation of nontopological magnetic solitons that may be regarded as skyrmions with a reversed core.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hierro Rodriguez, Dr Aurelio
• Authors: Navas, D., Verba, R.V., Hierro-Rodriguez, A., Bunyaev, S.A., Zhou, X., Adeyeye, A.O., Dobrovolskiy, O.V., Ivanov, B.A., Guslienko, K.Y., and Kakazei, G.N.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: APL Materials
• Publisher: AIP Publishing
• ISSN: 2166-532X
• ISSN (Online): 2166-532X
• Published Online: 16 August 2019
• Copyright Holders: Copyright © 2019 The Authors
• First Published: First published in APL Materials 7:081114
• Publisher Policy: Reproduced under a Creative Commons License