Despite theoretical predictions, it remains an experimental challenge to realize an artificial magnetic skyrmion whose topology can be well controlled and tailored so that its topological effect can be revealed explicitly in a deformation of the spin textures. Here we report epitaxial magnetic thin films in which an artificial skyrmion is created by embedding a magnetic vortex into an out-of-plane aligned spin environment. By changing the relative orientation between the central vortex core polarity and the surrounding out-of-plane spins, we are able to control and tailor the system between two skyrmion topological states. An in-plane magnetic field is used to annihilate the skyrmion core by converting the central vortex state into a single domain state. Our result shows distinct annihilation behaviour of the skyrmion core for the two different skyrmion states, suggesting a topological effect of the magnetic skyrmions in the core annihilation process.

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We report a study of the exchange bias of a high quality perovskite cobaltite La 0.82 Sr 0.18 CoO 3 single crystal with spin glass (SG) like nature. According to the dependence of exchange bias field on the cooling field, an antiferromagnetic (AFM) interfacial exchange coupling constant at the spin-glass region J i ≈ −0.68 meV was found. The size of the FM regions t FM ≈ 9 nm was estimated in the spin-glass system from the inverse proportion of exchange bias field H EB to the size of the FM regions.

Published by the AIP PublishingArticles you may be interested in Microstructure and magnetic properties of FeCo epitaxial thin films grown on MgO single-crystal substrates J. Appl. Phys. 105, 07C303 (2009); 10.1063/1.3067854Growth conditions to optimize chemical order and magnetic properties in molecular-beam-epitaxy-grown CoPt/MgO(001) thin films While a magnetic antivortex state can be created in ring structures, much effort has been devoted to stabilizing a magnetic antivortex as the ground state in a single island. Among many proposals, less attention has been paid to the role of magnetocrystalline anisotropy because most magnetic microstructures are made of polycrystalline materials. By patterning epitaxial Fe/Ag(001) films along different in-plane directions, we show that the Fe magnetocrystalline anisotropy plays a very important role in stabilizing different types of vortex/antivortex states. In particular, we find that an Fe island in the shape of an elongated hexagon favors vortex array formation when the long edge is parallel to the Fe easy magnetization axis, and favors the vortex-antivortex array formation when the long edge is parallel to the Fe hard magnetization axis. V C 2014 AIP Publishing LLC.

Magnetic vortex and antivortex are the two basic topological states in magnetic systems. While the ferromagnetic (FM) vortex state can be formed spontaneously and be imprinted into an antiferromagnetic (AFM) layer in AFM/FM disks, the antivortex state has never been realized in AFM films. By fabricating single crystalline NiO/Fe/Ag(001) microstructures, we show that the magnetic antivortex state can be created in the Fe microstructures and imprinted into the AFM NiO layer.