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Surface Composition Of CoXNi1-XO Solid Solutions By X-Ray Photoelectron And Auger Spectroscopies, M. W. Nydegger, G. Couderc, Marjorie Langell

Marjorie A. Langell Publications

The surface and bulk compositions of the mixed metal oxide Co_xNi_1-xO have been compared over the entire range of stoichiometry 0 ≤ x ≤ 1. The materials, which were formed as polycrystalline solid solutions, were shown to be well-ordered and homogeneous in the bulk, but tend to deviate in their surface composition for x > 0.6. Auger and X-ray photoelectron spectroscopy gave comparable results and indicated that the surface composition for samples showing deviation from bulk stoichiometry was compatible with the formation of a spinel-like NiCo₂O₄ surface phase. XPS binding energies and spectral …