Researchers at the University of Warwick have created a form of strontium manganite that operates at close to room temperature.
As reported in JACS, a new material marries magnetism and electrical polarisation in a union that could vastly increase the speed and sustainability of computer memory.
Magnetoelectrics are highly sought after as they allow magnetic information to be switched via an electric field, rather than a magnetic one. This increases the energy-efficiency of a computer and could prove invaluable as demand grows for data centres and AI systems, which draw huge amounts of processing power from the grid.
However, most magnetoelectric materials only work at extremely cold temperatures, which has inhibited wider deployment.
Overcoming the temperature hurdle
The researchers found a way around the temperature issue via a structural change: the atom pairs inside the strontium manganite’s crystal structure tilt in a coordinated way. This minor tilt generates an electrical charge across the material, as well as a weak, switchable magnetism.
The key difference is that the charge does not rely on the magnetism, as is the case in most magnetoelectrics, where the two are bound to each other and only survive in freezing temperatures. In the strontium manganite material, the structural shift and magnetism are independently stable and can survive at warmer temperatures.
“Finding a material that combines magnetism and electrical polarisation is hard enough on its own, but finding one that does this close to room temperature has been a real sticking point for the field,” said Dr Struan Simpson, Department of Chemistry, University of Warwick. “What’s exciting here is that the mechanism behind it is remarkably simple, a small, coordinated tilt within the crystal structure is all it takes. That simplicity is what makes us confident this approach can be applied much more widely.”
A simple structural change- with myriad applications
Using high neutron scattering and high-resolution X-rays, the teams confirmed that the effect persists in warmer and more practical temperatures. They also found that the effect could be strengthened with minor adjustments in the material’s chemistry, meaning future efforts to fine-tune performance could be relatively easy.
The diffraction measurements were carried out using two UK national facilities, the Diamond Light Source and the ISIS Neutron and Muon Source, alongside the ESRF synchrotron in France.
“This isn’t just about one material,” added Professor Mark Senn, Department of Chemistry, University of Warwick.”It gives us a blueprint for looking at a whole class of structures that were previously overlooked for this kind of application. The next step is exploring how far we can push these ideas, and how close we can get to a material that’s genuinely ready for use in real devices.”
The team believes the same design trick could be applied to a much wider range of materials, opening the door to new energy-efficient technologies beyond the one studied here.