A team of physicists claims to have discovered a new type of quasiparticle that appears to be found in all magnetic materials, suggesting that magnetism is not as static as previously thought.

First of all, what are quasiparticles? In some systems, such as electrical circuits, quasiparticles can emerge. For example, in clustered lithium atoms, electrons from the outer layers are able to move to the layers of other lithium atoms, taking their negative charge with them. But the vacancies themselves can be modeled as if they were also particles, with their own positive charge, moving through the system. You may think these quasi-particles are unimportant, but they can tell us how these systems work and are involved in everything from your electronic devices to the environment. heat transfer.

In a new study, University of Missouri researchers took a closer look at honeycomb-shaped nanoscopic neodymium (Nd) arrays with narrow structural components, discovering the new quasiparticle.

“Conventionally, domain wall kinetics is considered the driving mechanism for the dynamic behavior of nanostructured magnets, which requires the application of a magnetic field or electric current. However, at length scales approaching the limit of the single domain, which defines a restricted nanomagnet, the nature of the magnetic interactions and the resulting dynamic properties can change significantly,” the team explains in their paper.

“At small single domain length scales (∼10 nm), the competing energy between the exchange, anisotropy, and dipolar terms causes inherent fluctuations in the macroscopic magnetic correlation parameter. Therefore, a new dynamic mechanism can emerge, as evidenced by recent numerical studies of squeezed nanomagnets using the Landau-Lifshitz magnetization model.

The team discovered “vortex loop-shaped quasiparticles” existing in the structure, which exist in all magnetic materials, regardless of the strength of the magnetic field and the temperature of the material. Additionally, they found that the quasiparticles were surprisingly dynamic.

“We’ve all seen the bubbles that form in soda water or other carbonated drinks,” Carsten Ullrich, Curatorial Distinguished Professor of Physics and Astronomy at the University of Missouri, said in a statement. statement. “Quasiparticles are like these bubbles, and we found that they can move freely at remarkably fast speeds.”

These quasiparticles were then found in tight ferromagnetic permalloy nanomagnetic arrays, although the quasiparticles were freer to move in the honeycomb structures.

“In the honeycomb structure with nanoscale elements, the quasiparticles are not bound to ordered domains due to the restrictive nature of the nanomagnetic geometry which prevents the growth of ordered (antiferromagnetic) domains. , and therefore the quasiparticles are free to move,” the team adds in their paper.

Besides being interesting, and perhaps hinting at a deeper understanding of magnetism in general, the new quasiparticle could lead to practical discoveries. used such as creating a new generation of faster and more efficient electronics. Specifically, it could be useful in the field of spin electronics, or “spintronics“, where electron spin, rather than charge, is used to store and process information.

“The nature of the spin of these electrons is responsible for the magnetic phenomena,” added Deepak Singh, associate professor of physics and astronomy at the university and a specialist in spintronics. “Electrons have two properties: a charge and a spin. So instead of using the conventional charge, we use the spin or spin property. This is more efficient because rotation dissipates much less energy than charging.

Although exciting, there is still much to be discovered before it can be put to practical uses. But for now, know that there is a quasi-particle present in all magnetic materials, and we didn’t know it until now.

The study is published in Physical examination research.