Hot-Electron Scattering and the Rigid-Band Model in Ferromagnetic Ni and Ni-Al Alloys

The measured photoelectron energy distributions for Ni-Al alloys are essentially the same as those for pure Ni. They differ only in magnitude and in the relative heights of the low-energy peaks. Monte Carlo calculations based on the rigid-band model and nondirect optical excitations show that the difference in photoemission produced upon alloying can be explained quite simply. The difference arises from a change in electron-electron scattering which accompanies a change in the occupation of $d$ states. Values of the mean free path for electron-electron scattering for electrons 7 eV above the Fermi energy are about 70 and 100 Å, respectively, for pure Ni and 92% Ni alloy.