Dynamic pattern of Skyrmions observed
The illustration demonstrates skyrmions in one of their Eigen modes (clockwise). © Yotta Kippe/HZB
Tiny magnetic vortices known as skyrmions form in certain magnetic materials, such as Cu2OSeO3. These skyrmions can be controlled by low-level electrical currents – which could facilitate more energy-efficient data processing. Now a team has succeeded in developing a new technique at the VEKMAG station of BESSY II for precisely measuring these vortices and observing their three different predicted characteristic oscillation modes (Eigen modes).
Cu2OSeO3 is a material with unusual magnetic properties. Magnetic spin vortices known as skyrmions are formed within a certain temperature range when in the presence of a small external magnetic field. Currently, moderately low temperatures of around 60 Kelvin (-213 degrees Celsius) are required to stabilise their phase, but it appears possible to shift this temperature range to room temperature. The exciting thing about skyrmions is that they can be set in motion and controlled very easily, thus offering new opportunities to reduce the energy required for data processing.
Three different Eigenmodes expected
Theoretical work had predicted that it should be possible to use a high-frequency electric field to excite a group of skyrmions in the sample so that their cores will rotate all together, synchronously like a fish swarm, clockwise or counter-clockwise, or alternatively they can even exhibit a “breathing” motion. Now a team has succeeded in measuring the dynamics of these skyrmions in detail using a single-crystal sample of Cu2OSeO3.
First experimental observation at VEKMAG
The team succeeded at BESSY II in combining a spin-resolving method with an external microwave field. „The resonant magnetic scattering technique when combined with magnetic vectorial external fields shows where the spins are located in the lattice and how they are oriented in space, and all these for each elemental spin species that may exist in the specimen“, explains Dr. Florin Radu, at the Helmholtz-Zentrum Berlin (HZB), a physicist who developed and set up the VEKMAG end station in cooperation with partners from the Universität Regensburg, Ruhr University Bochum, and Freie Universität Berlin. The construction and continuing development of the VEKMAG station are supported by the German Federal Ministry of Education and Research (BMBF) and HZB.
Using electric field induced ferromagnetic resonance excitation and recording the x-ray intensity of a so called Bragg peak, the research group demonstrated experimentally for the first time that all three characteristic oscillation modes occur in Cu2OSeO3 – the team observed magnetic skyrmions turning clockwise, counterclockwise, and expanding and contracting ("breathing" mode). Those modes can be switched and turned around by changing the frequency of the microwave field: Each dynamic mode is achieved for a certain frequency, which further depends on the external magnetic field as well as on other intrinsic parameters of the sample. “This is a first step towards phase specific characterization of controlled skyrmion’s gyrational motion”, Radu says.
Phys. Rev. Lett. (2019): Ferromagnetic Resonance with Magnetic Phase Selectivity by Means of Resonant Elastic X-Ray Scattering on a Chiral Magnet; S. Pöllath, A. Aqeel, A. Bauer, C. Luo, H. Ryll, F. Radu, C. Pfleiderer, G. Woltersdorf, and C. H. Back
DOI: 10.1103/PhysRevLett.123.167201
- Spin waves inside a nano-oscillator imaged for the first timeFor the first time, researchers have directly imaged the magnetisation dynamics inside a spin Hall nano-oscillator — a nanoscale device that converts direct current into tunable microwave signals and is a promising building block for energy-efficient wireless communication and brain-inspired computing. A Swedish–German team led by the University of Gothenburg and Helmholtz-Zentrum Berlin (HZB) achieved this using time-resolved scanning transmission X-ray microscopy at the MAXYMUS instrument at BESSY II. The results, now published in Advanced Materials, reveal spin-wave features that had escaped previous, indirect measurement techniques.
- Marcel Risch has been appointed Professor at the Freie Universität BerlinMarcel Risch was appointed to a W2-S professorship in the Department of Physics at Freie Universität Berlin in August 2026. His research group has been transformed into the department 'Mechanisms of Sustainable Electrocatalysis'. Risch investigates the fundamental mechanisms of electrocatalytic reactions and, on this basis, develops knowledge- and data-driven strategies to improve electrocatalysts for the sustainable production of hydrogen, fuels and chemicals.
- BESSY II: High-resolution insights into individual biomolecules and catalystsVery small biological samples and even individual biomolecules can now be examined under near-physiological conditions with high confidence at the BESSY II infrared beamline with a newly validated and improved technique: The nanoscale infrared spectroscopy (s-SNOM) with ultra-thin silicon-based membranes. An international team demonstrated after an initial proof of concept, that high-resolution (a few tens of nanometres) nano-IR measurements reliably match expected far-field IR spectra in an aqueous environment. This methodological advance provides a solid foundation for studying biomaterials or observing catalytic processes in a liquid environment.