Light-induced magnetic phase unlocks future data storage

Skyrmions are tiny, tornado-like whirls within a material's magnetic field. Because of their small size and rapid movement, skyrmions can be used for faster data manipulation, making ideal candidates for next-generation data-storage.

Now, scientists led by Fabrizio Carbone at EPFL have created a new, light-based technique for producing skyrmions in an ordered and usable fashion. The team produced the skyrmions on copper oxide selenite (Cu₂OSeO₃), which belongs to a class of materials known “Mott insulators”, whose electrons are “stuck in place”, unable to move and conduct electricity. Mott insulators are used to study fundamental quantum phenomena, such as the emergence of exotic magnetic phases, and they are often used in research on quantum computing and energy-efficient electronics.

In their new method, the researchers shot the Cu₂OSeO₃ material with pulses of laser to excite it. Each burst of laser came at near-infrared wavelengths (780 nm and 1200 nm) and lasted around a quadrillionth of a second.

By precisely controlling these laser pulses, the scientists successfully triggered a new skyrmion phase in the material. Once created, the skyrmions rearranged themselves and remained stable for minutes, which is crucial for reliable and non-volatile data storage that ensure information remains intact during power outages and other disturbances.

“We found that we can induce the formation of magnetic skyrmions with a laser in a region of the phase diagram [a graph showing the different states of a material under different conditions] where they are not supposed to exist,”, says Carbone. “In an analogy, it is as if one was able to use light to make water form ice above 0 C temperature.”

He adds: “We also show that there is no other protocol, temperature ramping, or magnetic field sweeping [tuning the strength or direction of a magnetic field] that can put skyrmions there.”

Other contributors

• Max Planck Institute for the Structure and Dynamics of Matter
• EPFL Laboratory for Quantum Magnetism
• EPFL Crystal Growth Facility
• Lund University