Study shows that skyrmions and antiskyrmions can coexist at different temperatures

Ingrid Fadelli is a writer for the website Phys.org.

The particles and antiparticles have the same mass but have different electric charges.

Studies have shown that the same behavior should be seen in magnetic solitons. Magnetic solitons, or solitary waves, can be distinguished from other waves by their topological charge Q.

Magnetic solitons with opposite Q values should destroy each other. Skyrmions and antiskyrmions are created as particles in magnets.

One of the first experiments to test these predictions was carried out by researchers at Forschungszentrum Jlich. Their paper shows the creation and destruction of skyrmion - antiskyrmion pairs in a magnet.

The aim of the study was to reveal the particle-like properties of the magnetic solitons. A magnetic skyrmion is the most well-known type of soliton. An example of a rich family of magnets with a B20-type crystal structure can be found in an alloy of FeGe.

Kiselev and his colleagues began observing skyrmion bags, which have been predicted in prior theoretical work. The researchers created an ultra-thin film of the FeGe.

The researchers unveiled other interesting phenomena, which they found to be related to skyrmion antiparticles. In their new study, they used a technique known as transmission electron microscopy, which is the most established technique for in situ observation and image of magnetic texture in samples that are up to a few hundred nanometers thick.

The incident electron beam that travels through the sample interacts with the magnetic field that results from local variations in magnetization in the sample, allowing magnetic contrast to be recorded with nanometer spatial resolution The magnetic contrast of skyrmions and antiskyrmions made it possible for us to distinguish them.

One of the key ingredients behind successful observation of antiskyrmions was their use of a high quality FeGe plate. The sample was prepared using focused ion beam milling.

The shape of the sample affects the formation of closed domain walls at the edges. The nucleation of antiskyrmions under the application is dependent on the latter.

Prior to our work, it was thought that skyrmions and antiskyrmions couldn't coexist. Our work shows that it is possible. There is a chance that skyrmions and antiskyrmions can coexist over a wide range of temperatures and magnetic fields.

More studies of magnetic solitons of different charges and symmetry would be inspired by the findings of this team of researchers. New strategies to use magnetic solitons in spintronic devices may be possible because of the diversity of particle-like states.

To explore these strategies, the researchers need to conduct physical studies of magnetic solitons and find new materials in which magnetic solitons are present.

The existence of a wide variety of solitons that have not been observed yet is suggested by our work. We want to find a reliable protocol to gather experimental observations of exotic solitons, such as skyrmion bags and other three-dimensional solitons. The observation of exotic solitons should be possible in FeGe and other materials of this class.

More information: Fengshan Zheng et al, Skyrmion–antiskyrmion pair creation and annihilation in a cubic chiral magnet, Nature Physics (2022). DOI: 10.1038/s41567-022-01638-4

The Chiral magnetic skyrmions with arbitrary topological charge were written by Filipp N. There is a DOI titled "10.103/PhysRevB".

Journal information: Nature Physics , Physical Review B

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