Fast-tracking the perfect alloy: Synchrotron radiation reveals the ideal half-metal composition

In a breakthrough for materials science, a team of researchers from Japan, led by Professor Yuya Sakuraba of the National Institute for Materials Science, has used high-brilliance synchrotron radiation to swiftly pinpoint the optimal composition for Heusler alloys, a class of magnetic materials with great potential for mass-storage technologies.

Half-metals, particularly Heusler alloys, have long been of interest due to their ability to exhibit a ‘half-metallic’ electronic structure, which could revolutionise industries like data storage. However, achieving the perfect balance of spin polarisation - an essential property for half-metallic materials - has been a complex and time-consuming challenge. The spin polarisation ratio indicates how electrons align in the up and down directions, directly impacting a material's half-metallic properties. Since this ratio varies with the material's composition, scientists have struggled to identify the ideal mix of elements efficiently.

Traditional methods for determining spin polarisation have been slow and often indirect, but this new technique is set to change the game. By using the NanoTerasu synchrotron facility, which opened in April 2024, the researchers subjected cobalt-manganese-silicon Heusler alloy films to high-brilliance radiation. This fast, cutting-edge approach allowed them to rapidly determine the ideal atomic composition for maximum spin polarisation - 27% manganese by atomic weight. Their findings [1] have been published in the journal Science and Technology of Advanced Materials.

“This marks the first successful use of photoelectron spectroscopy at the NanoTerasu facility, and the experiment was completed in just one day,” sad Professor Sakuraba. "This significant reduction in time for spin polarisation evaluation opens up new possibilities not only for half-metallic materials but for a wide range of magnetic and spintronic technologies."

The team's breakthrough approach is poised to accelerate the development of next-generation mass-storage devices, such as high-capacity hard disk drives, and advanced spintronic devices. With this method, scientists can now optimise materials much more efficiently, driving innovation in the fields of data storage and beyond.

More information online

1. Science and Technology of Advanced Materials.