Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP)/Departamento de Física e Astronomia, Universidade do Porto, 4169-007 Porto, Portugal
R. V. Verba
Institute of Magnetism, National Academy of Sciences of Ukraine, 03142 Kyiv, Ukraine
A. Hierro-Rodriguez
Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP)/Departamento de Física e Astronomia, Universidade do Porto, 4169-007 Porto, Portugal
S. A. Bunyaev
Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP)/Departamento de Física e Astronomia, Universidade do Porto, 4169-007 Porto, Portugal
X. Zhou
Department of Electrical and Computer Engineering, National University of Singapore, 117583, Singapore
A. O. Adeyeye
Department of Electrical and Computer Engineering, National University of Singapore, 117583, Singapore
O. V. Dobrovolskiy
Physikalisches Institut, Goethe University, 60438 Frankfurt am Main, Germany
B. A. Ivanov
Institute of Magnetism, National Academy of Sciences of Ukraine, 03142 Kyiv, Ukraine
K. Y. Guslienko
Depto. Física de Materiales, Universidad del País Vasco, UPV/EHU, 20018 San Sebastián, Spain
G. N. Kakazei
Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP)/Departamento de Física e Astronomia, Universidade do Porto, 4169-007 Porto, Portugal
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.
