October 3, 2023


Sapiens Digital

Magnetic ‘Vortex Ring’ Matter – Trippy at First Sight?

Everywhere we find fluid, we’ll also find vortex rings. But recently, scientists discovered them in an intriguing place — inside a tiny pillar composed of magnetic material: the gadolinium-cobalt intermetallic compound called GdCo2, according to a recent study published in the journal Nature.


Trippy ‘vortex rings’ seen inside magnetic material for the first time

Typically when we think of material rings, we remember smoke or (underwater) bubble rings — and they’re formed when fluid flows back onto itself after making its way through the constricted space of a hole or tube.

The new study marks the first time vortex rings were identified in a magnetic material — and confirms a prediction decades in waiting. Additionally, it could also help scientists confirm even more complex magnetic structures theoretically predicted — ones we might use to develop new and inspiring technologies.

Magnetic ring vortex seen paired with antivortex 

Magnetic ring vortices were initially predicted more than 20 years ago — in 1998, when physicist Nigel Cooper of the University of Cambridge showed the world how magnetic vortices are not unlike the vortex rings we often see in fluid dynamics. The empirical search to witness them, however, was much harder to make fruitful.

Eventually, the technology required to image magnetization within a material beyond the surface layer was developed — in 2017. Researchers from ETH Zurich and the Paul Sherrer Institute created an X-ray nanotomography technique capable of capturing a 3D image of the magnetization structure within a GdCo2 magnet, Science Alert reports.

While engaged in the experiments, the researchers — under the leadership of Claire Donnelly from ETH Zurich — found vortices like those we see when we pull a sink out of water. Such vortices were even paired with their topological counterparts, called antivortices.

Magnetic ring structures ‘unexpectedly stable’

However, the vortices didn’t behave the way scientists thought they would. Fluid rings are constantly in motion and last for a short time, so they thought magnetic ring vortices would follow the same pattern of behavior — rolling through magnetic material before fading away.

Breaking with the theory, the new trippy vortices held still in a static state — vanishing only when the GdCo2 became annealed, or heated and exposed to strong magnetic fields — which is a process used to reorient magnetization.

“One of the main puzzles was why these structures are so unexpectedly stable — like smoke rings, they are only supposed to exist as moving objects,” said Donnelly, who now works with Cambridge University, according to Science Alert.

Studying magnetic vortex rings may help advance next-gen technology

“Through a combination of analytical calculations and considerations of the data, we determined the root of their stability to the magnetostatic interaction,” added Donnelly.

To simplify, these newly-observed vortices interact with magnetization structures surrounding them — holding the rings in place and causing stabilization. The study of how they form and hold a stable pattern might help physicists understand how they may control magnetic vortex rings — which may then help them build better, more advanced technologies, like neuromorphic engineering or data storage.

Vortex Ring Gun

A vortex ring as it exits a gun muzzle. Source: George Kenneth Lucey Jr. and Dr. D. Lyon (Army Research Laboratory), Frank Dindl (Armament Research, Development and Engineering Center) / Wikimedia

Every ring vortex we see hints at the trippy future of magnetic technology

Additionally, the newly-witnessed vortex rings might also help us better grasp magnetization itself. The role singularities play in magnetization processes, for example, isn’t the most well-developed body of science. The observation of vortex rings could also hint at other complex structures scientists might study in greater detail, like solitons — also called magnetic waves.

“The calculation and visualization of the magnetic vorticity and pre-images have proven essential tools in the characterization of the observed three-dimensional structures,” wrote the researchers in the new paper.

“The observation of stable magnetic vortex rings opens up possibilities for further studies of complex three-dimensional solitons in bulk magnets, enabling the development of applications based on three-dimensional magnetic structures,” the researchers added.

Whenever we look at ring patterns in smoke or patches of bubbly water, we’re seeing more than simple vortices of gas or liquid rolling back on itself — we’re catching a glimpse of a material behavior slated to play a role in the next generation of data storage, neuromorphic engineering, solitons, and much more — all as significant to future technologies as the rings themselves are trippy.

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