A research team led by Prof. DU Haifeng from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has achieved stable magnetic bundles at room temperature without the need for any external magnetic field.

Their work was published in Nature Communications.

Topological magnetic structures are a type of spin arrangement with nontrivial topological properties. These structures hold promise as next-generation data carriers and could overcome the limitations of traditional magnetic storage technologies in spintronics.

In previous research, the researchers proposed a method to induce magnetic skyrmion bundles in a chiral helimagnetic material called FeGe. However, achieving stable magnetic bundles at room temperature and without an external magnetic field remained a major challenge for practical applications in spintronics.

To address this challenge, the researchers ingeniously combined pulsed currents with reversed magnetic fields in the room-temperature chiral helimagnetic material Co₈Zn₁₀Mn₂. This approach allowed them to achieve a rich variety of room-temperature chiral magnetic skyrmions, avoiding the complex field-cooling processes required in previous skyrmion bundle generation.

Furthermore, they introduced a special zero-field vertical spiral domain magnetization background to stabilize the magnetic skyrmion bundles. By establishing a complete magnetic field-temperature phase diagram for skyrmion bundles, they finally achieved stable isolated magnetic skyrmion bundles at room temperature with zero external magnetic field under free boundary conditions.

This work could advance the development of topological spintronic devices by exploiting the freedom of topological parameter confinement, according to the researchers.

a. Magnetic skyrmion bundles with topological charge Q=2; b. Magnetic field vs temperature phase diagram of a stable skyrmion bundle with Q=2. (Image by ZHANG Yongsen)