Researchers from Uppsala University, Germany and the US have demonstrated that spin currents can be generated and transferred from one nano-scale metal layer to another in less than a picosecond. The researchers are using very short (femtosecond scale) light pulses which create spin currents that move super-fast through the nanostructured layers and transfer the spin.
Detecting the spin in such a short time is not easy, and they had to develop new technology to do so. They ended up using ultra-short x-ray flashes with a pulse length of just a few femtoseconds. The spin magnetic moment were measured using magnetic x-ray spectroscopy.