Magnetic and electronic properties of Ni films, surfaces, and interfaces

Results of various calculations lead to a unified understanding of the magnetic behavior of thin nickel films. We thus explain disparate experimental results. We report results for magnetic and electronic properties of Ni films of one to five atomic layers on Cu (100) and (111), of the Ni-Cu (100) and (111) interfaces, and of the Ni (100) and (111) surfaces. Results are in good agreement with the few published calculations. We find that magnetization is suppressed at the Ni-Cu interface, but enhanced in isolated thin films. The net effect of this competition is that a Ni monolayer is substantially magnetic on Cu (100) but paramagnetic (or nearly so) on Cu (111). Film magnetization is found to be very sensitive to substrate composition. For substrates which couple strongly to the Ni film, ferromagnetism first appears at about three atomic layer Ni, in quantitative agreement with experiments based on Al and Pb-Bi substrates. The crucial mechanism acting to suppress Ni magnetization is sp-d hybridization, just as in most Ni alloys.