| AVS 61st International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Tuesday Sessions |
| Session MI+MG-TuM |
| Session: | Advanced Materials Discovery |
| Presenter: | Peter Fischer, Lawrence Berkeley National Laboratory |
| Authors: | R. Streubel, IFW Dresden, Germany L. Han, IFW Dresden, Germany M.-Y. Im, Lawrence Berkeley National Laboratory F. Kronast, Helmholtz-Zentrum Berlin für Materialien und Energie/Elektronenspeicherring BESSY II, Germany U.K. Roessler, Institute for Theoretical Solid State Physics, IFW Dresden, Germany F. Radu, Ruhr-Universitaet Bochum, Germany R. Abrudan, Ruhr-Universitaet Bochum, Germany G. Lin, IFW Dresden, Germany O.G. Schmidt, IFW Dresden, Germany P. Fischer, Lawrence Berkeley National Laboratory D. Makarov, IFW Dresden, Germany |
| Correspondent: | Click to Email |
Topological states in magnetism, such as chiral skyrmions, with an integer topological charge are currently a topic of intensive fundamental research [1-3]. If one was able to control their properties in a digital manner, such as switching their topological charge deliberately in storage devices, a novel path in spintronics would be opened [4]. However, so far, most of these topological spin textures have been only observed in exotic materials with low symmetry and at low temperatures, making them rather impractical for applications. Here, we offer an alternative route by designing synthetic magnetic heterostructures where specific spin textures resembling swirls, vortices or skyrmions with distinct topological charge densities can be tailored at ambient temperatures. This is achieved by vertically stacking two magnetic nanopatterns with in-plane and out-of-plane magnetization and imprinting the in-plane non-collinear spin textures into the out-of-plane magnetized material. Key mechanisms of our concept are demonstrated both by micromagnetic simulations and experimental observations with element-specific magnetic soft x-ray microscopy [6] in a common ferromagnetic thin film element stack, e.g. Co/Pd multilayers coupled to Permalloy. Utilizing the interlayer coupling strength as tuning parameter, a gradual transition in the magnetic pattern of the out-of-plane layer from the decoupled magnetized state to a strongly coupled state with a vortex spin texture is achieved. At an intermediate coupling strength, magnetic spirals with tunable opening angle and in particular donut textures form which can be referred to as skyrmion system with Dn symmetry. Applying a small magnetic field, a controlled and reliable switching between two topologically distinct donut textures is realized.
Supported by the German Science Foundation (DFG) grant MA 5144/1-1, the European Research Council under European Union's Seventh Framework program (FP7/2007-2013)/ERC grant agreement n.306277. M.-Y.I. and P.F. acknowledge support by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the U.S. Department of Energy under Contract No. DEAC02-05-CH11231 and by Leading Foreign Research Institute Recruitment Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (MEST)(2012K1A4A3053565).
[1] X.Z. Yu et al, Nature 465 901 (2010)
[2] F. Jonietz et al, Science 330 1648 (2010)
[3] S. Heinze et al, Nat. Phys. 7 713 (2011)
[4] A. Fert et al, Nat. Nano 8 152 (2013)
[5] J. Sampaio et al, Nat. Nano 8 839 (2013)
[6] P. Fischer et al, JESRP 189 196 (2013)