MOSSBAUER-EFFECT EMISSION-SPECTROSCOPY AND AUGER-ELECTRON SPECTROSCOPY STUDY OF THE (111)NI SURFACE

Mössbauer effect emission spectroscopy (MEES) and Auger electron spectroscopy were combined in an ultrahigh vacuum system to study the ferromagnetic (111) Ni surface. Preliminary data on a strained and roughened surface with nearly a monolayer of contamination are presented. The MEES spectra show broad resonances arising from a distribution of hyperfine fields. With an oxygen coverage of 0.15 monolayer (ML), surface sites with magnetic hyperfine fields larger than that for bulk nickel account for 30% of the total resonant absorption area. Fields larger than 130 kG can account for 70% of the absorption area despite 0.4 ML of carbon coverage. With 0.5 ML oxygen coverage the average hyperfine field is greatly increased. © 1979.