Steering magnetic textures with electric fields

With AI and data centers demanding more and more energy, scientists are searching for smarter, greener technologies. That’s where magnetoelectric materials come in - special compounds where electric and magnetic properties are linked. This connection lets researchers control magnetism using electric fields, which could pave the way for super-energy-efficient memory and computing devices.

One such magnetoelectric material is the olive-green crystal copper oxyselenide (Cu₂OSeO₃). At low temperatures, the atomic spins arrange themselves into exotic magnetic textures, forming structures such as helices and cones. These patterns are much larger than the underlying atomic lattice and not fixed to its geometry, making them highly tuneable.

Neutrons watch as electric fields redirect magnetism

Now, scientists at PSI have demonstrated that an electric field can steer these magnetic textures inside copper oxyselenide. In typical materials, magnetic structures – formed from the twisting and alignment of atomic spins - are locked in specific orientations. In copper oxyselenide with the right voltage, the researchers could nudge and reorient them. 

This is the first time that the propagation direction of a magnetic texture could be continuously reorientated in a material using an electric field – an effect known as magnetoelectric deflection.

To investigate the magnetic structures, the team used the SANS-I beamline at the Swiss Spallation Neutron Source SINQ, a facility that uses beams of neutrons to map the arrangement and orientation of magnetic structures within a solid at the nanoscale. A custom-designed sample environment enabled the researchers to apply a high electric field whilst simultaneously probing the magnetisation inside the crystal with small-angle neutron scattering (SANS).

“The ability to steer such large magnetic textures with electric fields shows what’s possible when creative experiments are paired with world-class research infrastructures,” says Jonathan White, beamline scientist at PSI. “The reason we can capture such a subtle effect as magnetoelectric deflection is due to the exceptional resolution and versatility of SANS-I.”

From novel physics to new tech

The newly discovered magnetoelectric deflection response prompted a deeper investigation into its underlying physics. What they found was intriguing: the magnetic structures didn’t just respond - they behaved in three distinct ways depending on the strength of the electric field. Low electric fields gently deflected the magnetic structures with a linear response. Medium fields brought in more complex, non-linear behaviour. High fields caused dramatic 90-degree flips in the direction of propagation of the magnetic texture.

“Each of these regimes present unique signatures that could be integrated into sensing and storage devices,” says Sam Moody, postdoctoral researcher at PSI and lead author of the study. “One particularly exciting possibility is hybrid devices that use the ability to tune the onset of these regimes by varying the strength of the applied magnetic field.”

The magnetoelectric deflection response offers a powerful new tool to control magnetism without relying on energy-intensive magnetic fields. The high level of flexibility with which the researchers could manipulate the magnetism makes their discovery an exciting prospect for applications in sustainable technology.