
For the first time ever, scientists have been able to directly observe spin waves—tiny ripples of magnetism known as magnons—at the nanoscale.
This exciting discovery marks a major step forward in the field of magnetism and could lead to new types of energy-efficient electronics in the future.
The breakthrough came from an international team of researchers, led by scientists at Uppsala University in Sweden, and was recently published in Nature.
By combining a powerful electron microscope with new theoretical tools, the team was able to see magnons in unprecedented detail.
Magnons are waves of energy that travel through magnetic materials like iron or nickel.
They are created by the tiny magnetic fields, or “spins,” of atoms as they shift and move together in a coordinated pattern—like a synchronized dance. These waves don’t carry electric charge, but they can carry information.
That’s why researchers are excited about using them in a new field called magnonics, which aims to replace electric currents in electronics with spin waves. This could allow for devices that are faster, smaller, and more energy efficient than today’s electronics.
Until now, however, observing magnons at the nanoscale—just billionths of a meter—was nearly impossible. Scientists could only see them on surfaces or detect them indirectly. But now, that’s changed.
“We could suddenly see all the magnons and every step of their dance at the nanoscale,” said Dr. José Ángel Castellanos-Reyes, co-lead author of the study and researcher at Uppsala University. “It was like getting front-row seats to a performance no one had ever seen in full.”
The researchers used a special type of electron microscope at the SuperSTEM laboratory in the UK. This microscope can detect extremely small changes in energy—just a few millionths of an electron volt—as an electron beam passes through a material. These tiny changes revealed the presence of magnons moving through nickel oxide nanocrystals, a model magnetic material.
Key to the discovery were two theoretical tools developed at Uppsala University. One, called TACAW (Time Autocorrelation of Auxiliary Wavefunctions), predicted how magnons would interact with the fast-moving electrons in the microscope.
The other, UppASD (Uppsala Atomistic Spin Dynamics), is a powerful computer program used to simulate how spins behave in magnetic materials. These tools helped the team understand the signals they were seeing and confirm they were, in fact, magnons.
According to Dr. Ján Rusz, a physics professor at Uppsala, the predictions made with these tools matched the experimental results exactly—offering a powerful validation of the new technique.
This achievement is more than just a technical milestone—it opens the door to entirely new ways of studying and designing magnetic materials. It could eventually lead to advances in magnonic devices, where information is transferred using spin waves instead of electric currents.
“This is a milestone in both microscopy and the study of spin-based technologies,” Castellanos-Reyes said. “It brings us one step closer to a new era of low-energy, high-speed electronics.”