US team sees tiny spinning waves called magnons moving in magnets

A research team at Brookhaven National Laboratory has achieved the first direct observation of magnon spin currents using resonant inelastic X-ray scattering (RIXS), marking a significant advancement in spintronics. Unlike previous methods that detected spin currents indirectly by converting them into electrical signals, this approach allowed scientists to measure the momentum distribution of magnons—quantized spin excitations carrying angular momentum—in a magnetic insulator (yttrium iron garnet, YIG) under a temperature gradient. The RIXS technique was sensitive enough to detect subtle imbalances in magnon intensity, providing a microscopic view of how magnons move and carry spin current without involving electron charge transport. This breakthrough is crucial for developing future energy-efficient spintronic devices, which rely on controlling spin currents to store and transmit information at higher densities. By applying a mathematical model, the team could calculate magnon lifetimes and dynamics, offering insights essential for magnon-based technologies. The researchers plan to extend their work to thin films