Transmission Mössbauer and FTIR spectroscopic studies of binary nickel(II)-iron(III) hydroxide systems

Transmission Mossbauer and Fourier transform infrared spectroscopic data obtained for binary nickel(II)-iron(III) hydroxide systems in a broad range of compositions (3 to 60 at.% Fe (Ni+Fe) ) are compared. Structural transformations of the samples and their surface layers are considered, depending on their bulk gross compositions. The formation of a nickel ferrite precursor is shown to be promoted in the crystallites surface layers even at much lower gross Fe-to-Ni ratios than that in NiFe2O4 owing to surface enrichment with iron, as confirmed by Auger electron spectroscopic analyses.