Spin-flip low-energy electron exchange scattering in NiO(100)

Electron exchange processes in NiO have been examined by complete spin-polarized electron energy loss spectroscopy. The measurements show a complicated dependence of the spin-flip exchange scattering on incident angle and energy, unexpected from existing theories and measurements on atoms and ferromagnets. The amount of exchange processes is dramatically enhanced in specular scattering geometry for incident energies around 30, 38 and 100 eV, which is attributed to resonant excitation.