High-resolution spin-polarized electron-energy-loss data on Ni(110) are presented. Exchange scattering is found to be the dominant loss mechanism. The Stoner excitation spectrum shows a sharp threshold around 65-meV energy loss (Stoner gap). The energy-loss probability for spin-down electrons is up to 3 times larger than for spin-up electrons. An interpretation in terms of the Ni 3d band structure is given.

• Received 26 October 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.1157