A research team led by Colorado State University graduate student Luke Wernert and Associate Professor Hua Chen has identified a previously unknown type of Hall effect that could lead to more energy-efficient electronic devices.
Their study, published in Physical Review Letters, was conducted in collaboration with graduate student Bastián Pradenas and Professor Oleg Tchernyshyov of Johns Hopkins University. The researchers uncovered evidence of a new property, dubbed the “Hall mass,” in a class of complex magnetic materials known as noncollinear antiferromagnets.
The traditional Hall effect, discovered by Edwin Hall at Johns Hopkins in 1879, describes how an electric current is deflected sideways when subjected to an external magnetic field, generating a measurable voltage. This effect plays a crucial role in technologies such as vehicle speed sensors and smartphone motion detectors.
But in the CSU team’s work, electrons’ spin (a tiny, intrinsic form of angular momentum) takes center stage instead of electric charge. Noncollinear antiferromagnets, unlike more familiar magnets where spins line up parallel or antiparallel, have spins oriented in different directions but still sum to zero net magnetization. This unique spin texture enables a fresh take on the Hall effect, where spin currents can flow at right angles rather than just electric charges.
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