Scientists Develop Quantum Sensor Scheme to Detect Altermagnets

Physicists from the University of Buffalo introduced a quantum sensor scheme for altermagnets.

Physicists from the University of Buffalo have introduced a theoretical scheme for a quantum sensor designed to detect altermagnets—a new class of magnetic materials. This was reported by Quantum Insider.

The study was published in Physical Review Letters. It does not introduce a new type of magnetism but rather a method to detect altermagnetic order. The system currently exists only on paper, with experimental verification yet to come.

The concept involves using a diamond with a nitrogen-vacancy (NV-center) defect: a nitrogen atom and an adjacent vacancy in the lattice. This defect is sensitive to local magnetic fields. It is placed near a suspected altermagnet, with its spin oriented in various directions to measure relaxation rates. Anisotropic relaxation could indicate a complex magnetic order—a hallmark of altermagnets.

The authors advocate for a less invasive approach. Existing methods often affect the sample too strongly, making it difficult to separate the material’s intrinsic properties from measurement effects.

The corresponding author is Jamir Marino, an assistant professor of physics at the University of Buffalo. Co-authors include Libor Šmejkal and Jairo Sinova from Johannes Gutenberg University Mainz, who are credited with first proposing the concept of altermagnets. The study also involved Hossein Hosseinnabadi and V.A.S.V. Bittencourt.

Interest in altermagnets is growing due to their potential applications in electronics. These materials combine zero net magnetization, like antiferromagnets, with the electronic effects of ferromagnets. The potential lies in faster and more energy-efficient information transfer.

Signs of altermagnetism have already been observed in several materials. Theoretical calculations point to over 200 potential compounds, increasing the demand for precise identification methods.

The key outcome of the study is not a ready-made sensor but a measurement protocol. This could form the basis for future experiments to search for and confirm altermagnetic order.

In May, Quantinuum and energy giant BP launched a joint project to apply quantum computing for subsurface sensing and mapping of the Earth’s interior.