Image Courtesy: Libor Šmejkal & Anna Birk Hellenes
Scientists have proposed a new way to identify one of the newest and most intriguing classes of magnetic materials by using a tiny defect inside a diamond. If proven in experiments, the technique could help researchers confirm the existence of altermagnets, materials that may one day enable faster and more energy-efficient electronic devices.
The research, led by physicists at the University at Buffalo, describes a quantum sensing approach that relies on a microscopic defect in a diamond to detect subtle magnetic behavior. By measuring how the defect’s magnetic signal changes over time near a candidate material, researchers believe they could identify the unique magnetic patterns associated with altermagnets. The findings were published in Physical Review Letters.
For decades, scientists recognized only two primary types of magnets: ferromagnets, which are commonly found in household items such as refrigerator magnets, and antiferromagnets, whose magnetic properties cancel out at the atomic level. In recent years, researchers proposed a third category called altermagnets, which appear to combine the fast switching capabilities of antiferromagnets with some of the electronic advantages of ferromagnets.
The concept first emerged in 2019 after researchers observed unexpected magnetic behavior in ruthenium dioxide that existing theories could not fully explain. Since then, theoretical studies have suggested that more than 200 materials could belong to this new class, making reliable detection methods increasingly important.
The proposed sensing technique uses a diamond containing a nitrogen-vacancy defect, created when a nitrogen atom replaces a carbon atom next to a missing carbon atom. These defects are extremely sensitive to nearby magnetic fields. Researchers would rotate the defect’s magnetic spin and measure how quickly it relaxes. Variations in the relaxation rate could reveal the hidden magnetic patterns expected in altermagnets without significantly disturbing the material itself.
Although the method currently exists only as a theoretical model, researchers believe it could become an important tool for validating altermagnets experimentally. If successful, the discovery could accelerate the development of next-generation electronics that process information more efficiently while consuming less power.
