Researchers from the Hebrew University of Jerusalem in Israel, Tiangong University in China, and the Chinese Academy of Sciences have reported an innovative method that advances the understanding of spin dynamics in textured magnets and could facilitate the development of spintronic technologies based on frustrated magnetic systems.
Magnetic skyrmions excited by currents of spin polarized electrons (Illustration)
The team's approach presents a new way to manipulate and track the motion of tiny magnetic structures known as skyrmions, that has the potential to enable more efficient memory and sensing devices in future electronics.
Led by Prof. Amir Capua and Phd. Candidate Nirel Bernstein from the Institute of Applied Physics and Nano Center at Hebrew University in collaboration with Prof. Wenhong Wang and Dr. Hang Li from Tiangong University, the team explored how skyrmions behave in a special magnetic material called Fe₃Sn₂ (iron tin). This material is already known to be promising for use in advanced technologies because it keeps skyrmions stable even at extreme temperatures - a key requirement for practical devices.
The team discovered that by sending electrical currents through Fe₃Sn₂, they could excite certain kinds of “resonances” in the skyrmions - essentially making them vibrate in very specific ways. These vibrations, or “modes,” were detected using advanced optical techniques that observe changes in real time.
Interestingly, only two types of motion were triggered: a “breathing” mode (expanding and contracting like lungs) and a rotating motion. This confirmed earlier scientific predictions and suggests that Fe₃Sn₂ behaves differently from other magnetic materials.
The researchers also noticed that the width of the resonance signal changed when they applied a steady current. Using computer simulations, they showed that this effect was caused by a “damping-like torque” which indicates the presence of spin polarized currents. Furthermore, they realized that the resoanances of the magnetic swirles were excited due to “spin-orbit torque” rather than the more familiar “spin-transfer torque”.
“This gives us a deeper understanding of how spin currents interact with magnetic materials, especially in systems where the internal magnetic structure is frustrated or disordered,” said Prof. Capua.
They also found signs that both real-space and momentum-space spin structures play a role in how electrons and spins move through the material, offering new clues about how to control electrical signals in future devices.
Not only does this research reveal new physics behind spin-torque effects, but it also opens up possibilities for using skyrmion resonances as highly sensitive detectors of spin currents - which could advance data storage, neuromorphic computing, and sensor technologies.