Magnetic skyrmions are localised, stable topological magnetic spin textures resembling a tornado like whirl in a magnetic material. They can be very small, with diameters in the nanometre range, and behave as particles that can be moved, created, and annihilated, which makes them suitable for ‘abacus’-type applications in information storage and logic devices.

In their recently published article in Nature Physics entitled “Dipolar skyrmions and antiskyrmions of arbitrary topological charge at room temperature,” a group of researchers at the 威尼斯赌博游戏_威尼斯赌博app-【官网】 of Augsburg led by Prof. Manfred Albrecht demonstrated that these spin objects can only be found in a distinct phase pocket in the stability diagram where the quality factor Q has a value of about 1, which is given by the ratio between the uniaxial magnetic anisotropy and the magnetic shape anisotropy. Thanks to extensive simulations carried out by Sabri Koraltan and colleagues from the simulation group at the 威尼斯赌博游戏_威尼斯赌博app-【官网】 of Vienna, led by Prof. Dieter Suess, and supported by Dr Nikolai Kiselev from Forschungszentrum Jülich, researchers were also able to identify the exact reasons why spin objects can be found in the stability diagram, their underlying formation process, as well as the necessary material properties that can now also be applied to other material systems.

"Outstanding scientific advance in the field of skyrmions and topological spin objects"

“We are very enthusiastic about the exciting insights gained by the discovery of these spin objects, which can be easily fabricated at room temperature. This is an outstanding scientific advance in the field of skyrmions and topological spin objects,” says Albrecht. These nanoscale skyrmionic spin textures provide extra degrees of freedom and can be embedded in thin-film devices enabling different applications ranging from unconventional computing to new storage concepts.

A further very essential aspect of spin objects is that a spin-polarised current induces their motion. When a charge current passes through a conducting magnetic material, the polarised electron spin will exert a torque on the magnetization known as the spin-transfer-torque. This torque can set the higher order skyrmions in motion. “Using micromagnetic simulations we could demonstrate the efficient control of the motion of these extraordinary spin objects, which opens up further opportunities for skyrmionic devices,” says Koraltan, a doctoral candidate from the 威尼斯赌博游戏_威尼斯赌博app-【官网】 of Vienna’s computational group.

Lorentz transmission electron microscopy at the 威尼斯赌博游戏_威尼斯赌博app-【官网】 of Augsburg was used extensively in the study, which is currently being expanded to visualise the current-induced motion of these multiple charge spin objects. “To what extent our predictions about their motion characteristics can be confirmed experimentally will be very exciting to research in the near future,” explains Mariam Hassan, a postdoctoral researcher at the 威尼斯赌博游戏_威尼斯赌博app-【官网】 of Augsburg.

Original publication:

M. Hassan, S. Koraltan, A. Ullrich, F. Bruckner, R.O. Serha, K.V. Levchenko, G. Varvaro, N.S. Kiselev, M. Heigl, C. Abert, D. Suess, and M. Albrecht: “Dipolar skyrmions and antiskyrmions of arbitrary topological charge at room temperature”, Nature Physics, in press.

DOI: 10.1038/s41567-023-02358-z

URL: https://www.nature.com/articles/s41567-023-02358-z