Figure 1 illustrates the alignment of magnetic spins in a hopfion ring, as captured by Philipp Rybakov.
Recently, hopfions, which are intricate magnetic spin structures anticipated for years, have garnered significant attention in scientific research. A collaborative study involving teams from Sweden, Germany, and China, published today in the journal Nature, provides the first experimental validation of these structures.
Philipp Rybakov from Uppsala University’s Department of Physics and Astronomy comments, “This research is pivotal both fundamentally and practically, as it bridges experimental physics with complex mathematical theories, potentially paving the way for hopfions in spintronic applications.”
Understanding the functioning of material components is crucial for developing innovative materials and future technologies. For instance, spintronics explores electron spin and has revealed exciting opportunities to merge electron-based electricity and magnetism for new electronic applications.
Figure 2 displays experimental images (snapshots from an over-focused Lorentz transmission electron microscopy image of a hopfion ring in a 180 nm-thick FeGe plate under varying magnetic fields), credited to Fengshan Zheng of Forschungszentrum Jülich.
Topological structures like magnetic skyrmions and hopfions, known for their particle-like qualities, have been central to research for the last decade, especially in spintronics. Skyrmions are two-dimensional, resembling vortex strings, whereas hopfions are three-dimensional, resembling twisted skyrmion strings in a donut shape (Figure 1).
Despite considerable research, the direct observation of magnetic hopfions was previously limited to synthetic materials. This study marks the first experimental detection of such states in B20-type FeGe crystal plates, using transmission electron microscopy and holography (Figure 2). The findings align with micromagnetic simulations, are highly reproducible, and contribute to the classification and understanding of topological solitons in three-dimensional chiral magnets.
Dr. Philipp Rybakov, a postdoctoral researcher and the corresponding author from the Department of Physics and Astronomy, Materials Theory, Uppsala University, Sweden, is also credited (photograph by Ekaterina Dedyukhina).
These discoveries introduce new avenues in experimental physics, such as identifying other crystals where hopfions are stable, exploring their interactions with electric and spin currents, their dynamics, and more.
“Given the novelty of hopfions and the yet-to-be-discovered properties, predicting specific spintronic applications is challenging. Nonetheless, hopfions could significantly enhance three-dimensional aspects of technologies currently developed with magnetic skyrmions, such as racetrack memory, neuromorphic computing, and qubits. Their three-dimensional nature offers an additional degree of freedom compared to skyrmions, allowing movement in three dimensions,” elaborates Rybakov.
The study is referenced as “Hopfion rings in a cubic chiral magnet,” published on 22 November 2023 in Nature.
Frequently Asked Questions (FAQs) about hopfions
What are Hopfions?
Hopfions are complex three-dimensional magnetic spin structures that have been a subject of theoretical prediction and recent experimental research. They are notable for their unique topological properties and potential applications in advanced technology fields like spintronics.
How were Hopfions experimentally observed?
Hopfions were experimentally observed in a B20-type FeGe crystal plate using transmission electron microscopy and holography. This marks the first time such structures have been stabilized and directly observed in crystal plates, aligning with previous theoretical predictions and micromagnetic simulations.
What makes Hopfions significant in research and technology?
Hopfions are significant due to their unique three-dimensional structure and particle-like properties, offering new possibilities in the field of spintronics. Their ability to function in three dimensions makes them potentially more versatile than two-dimensional magnetic structures like skyrmions.
What future applications could Hopfions have?
While specific applications of hopfions in spintronics are still being explored, they are speculated to enhance technologies like racetrack memory, neuromorphic computing, and qubits. Their additional degree of freedom in three-dimensional space could lead to significant advancements in these areas.
Who conducted the research on Hopfions?
The research on hopfions was conducted by a collaborative team involving researchers from Sweden, Germany, and China. The team presented their findings in the journal Nature, showcasing the first experimental evidence of hopfions in crystal plates.
More about hopfions
- Hopfions in Magnetic Materials
- Spintronics and Future Technology
- Experimental Discovery of Hopfions
- Magnetic Structures in Spintronics
- Nature Journal: Hopfion Research Article