Despite their small size, nanomagnets — found in most spintronics applications — reveal rich dynamics of spin excitations, or “magnons,” the quantum mechanical units of spin fluctuations. Due to its nanoscale confinement, a nanomagnet can be viewed as a zero-dimensional system with a discrete magnon spectrum, similar to the spectrum of an atom.

“The magnons interact with each other, thus constituting nonlinear spin dynamics,” said Igor Barsukov, assistant professor of physics and astronomy at UC Riverside and corresponding author of the study published in the journal. Applied physical examination. “Nonlinear spin dynamics is a major challenge and a major opportunity to improve the performance of spintronic technologies such as spin torque memory, oscillators and neuromorphic computing.”

Barsukov explained that the interaction of magnons follows a set of rules — the selection rules. Researchers have now postulated these rules in terms of symmetries of magnetization patterns and magnon profiles.

The new work continues efforts to tame nanomagnets for next-generation computing technologies. In a previous publication, the team demonstrated experimentally that symmetries can be used for engineering magnon interactions.

“We recognized the opportunity, but also noticed that there was still a lot of work to be done to understand and formulate the selection rules,” Barsukov said.

According to the researchers, a comprehensive set of rules reveals the mechanisms behind the magnon interaction.

“It can be seen as a guide for spintronics labs for debugging and designing nanomagnet devices,” said Arezoo Etesamirad, the paper’s first author who worked in the Barsukov lab and recently earned a doctorate in physics. “It lays the foundation for the development of a set of experimental tools for tunable magnetic neurons, switchable oscillators, energy-efficient memory, and next-generation quantum nanomagnetic and other applications.”

Barsukov and Etesamirad were joined in the search by Rodolfo Rodriguez of UCR; and Julia Kharlan and Roman Verba of the Institute of Magnetism in Kyiv, Ukraine.

The study was funded by the US National Science Foundation, National Academy of Sciences of Ukraine, National Research Foundation of Ukraine, National Science Center of Poland, and NVIDIA Corporation.