Manipulating topological states by imprinting non-collinear spin textures.

Robert Streubel,Mi-Young Im,Gungun Lin,Florian Kronast,Oliver G Schmidt,Luyang Han,Denys Makarov,Florin Radu,Ulrich K Rößler,Radu Abrudan,Peter Fischer

doi:10.1038/srep08787

Abstract

Topological magnetic states, such as chiral skyrmions, are of great scientific interest and show huge potential for novel spintronics applications, provided their topological charges can be fully controlled. So far skyrmionic textures have been observed in noncentrosymmetric crystalline materials with low symmetry and at low temperatures. We propose theoretically and demonstrate experimentally the design of spin textures with topological charge densities that can be tailored at ambient temperatures. Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can be imprinted into the out-of-plane magnetised material. We observe distinct spin textures, e.g. vortices, magnetic swirls with tunable opening angle, donut states and skyrmion core configurations. We show that applying a small magnetic field, a reliable switching between topologically distinct textures can be achieved at remanence.

Highlights

Correspondence and requests for materials should be addressed to Manipulating Topological States by Imprinting Non-Collinear Spin Textures
Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can be imprinted into the out-of-plane magnetised material
Chiral skyrmions have been only observed in single-phase materials with acentric crystal structures[5,6,17,18,19,20] or in magnetic films owing to broken inversion symmetry[7,14,21,22] and at low temperatures that severely limits their potential application in spintronics

Summary

Correspondence and requests for materials should be addressed to

Robert Streubel[1], Luyang Han[1], Mi-Young Im2,3, Florian Kronast[4], Ulrich K. An alternative route to exploit topological properties of magnetisation distributions is to create magnetic heterosystems exhibiting non-collinear spin textures These nontrivial topological states generate a topological charge density which instills Berry phases and transport anomalies. We propose theoretically and demonstrate experimentally nontrivial topological states by imprinting non-collinear spin textures into an out-of-plane magnetised material via stacking two magnetic nanopatterns consisting of layers with in-plane and out-of-plane magnetisation. Within such heterostructures, it is possible to www.nature.com/scientificreports. The net charge is governed by an opening angle of the spin texture that can be precisely controlled by tuning the interlayer exchange coupling between inplane and out-of-plane magnetic substructures and applying small magnetic fields. We prove that the interlayer coupling strength can be tailored by adjusting the thickness d of the non-ferromagnetic Pd spacer layer between Permalloy and Co/Pd layers

Theoretical predictions

Methods

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Additional information