A key step for this technology is controlling spin currents, which are notoriously difficult to measure. Until now, scientists typically converted a spin current into an electrical signal to detect it,\u00a0a process that obscures\u00a0direct spin information.<\/p>\n
\u201cA\u00a0pure spin current has never\u00a0been measured\u00a0directly because the associated electric stray fields and\/or shifts in the non-equilibrium spin-dependent distribution functions are too small for conventional experimental detection methods optimized for charge transport,\u201d\u00a0added\u00a0the study<\/a>.<\/p>\n Using the RIXS technique<\/p>\n Led by scientists at the National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory, the team used a technique called resonant inelastic X-ray scattering (RIXS).\u00a0<\/p>\n By applying a temperature gradient, they created a device that generates a magnon spin current within a magnetic insulator, yttrium iron garnet (YIG). Magnons are quantized excitations that carry angular momentum in a\u00a0material\u2019smagnetic structure.<\/p>\n \u201cOur goal was to reveal the magnons involved in spin currents,\u201d\u00a0said Yanhong Gu, former postdoctoral fellow in\u00a0Bisogni\u2019s\u00a0group.\u00a0<\/p>\n \u201cThese are not moving spins, but moving angular momenta forming a spin wave, while the electron charges remain still.\u201d<\/p>\n The RIXS technique proved sensitive enough to detect small imbalances in the magnon intensity, which reflected changes in the magnon distribution as they moved.\u00a0This\u00a0provided a microscopic picture of which\u00a0specific excitations<\/a>\u00a0carried the spin current and at what momentum.<\/p>\n
![\"An](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2025\/09\/Spin.jpg\" "\\"US")
An artist\u2019s representation of the spin current generated in yttrium iron by the spin Seebeck effect. Image credit: