CHARACTERIZATION OF THE SPINELS M(X)CO(1-X)FE(2)O(4) (M=MN,FE OR NI) USING X-RAY PHOTOELECTRON-SPECTROSCOPY

X-ray photoelectron spectra have been recorded from a series of charac terised cobalt-iron containing spinels M(x)Co(1-x)Fe(2)O(4) where M = Mn, Fe or Ni and 0 less than or equal to x less than or equal to 1. Th e binding energies of photoelectron peaks observed for the transition metal ions were recorded. Changes in their relative positions were not ed and the measured intensities used to determine the surface composit ion. The observed surface segregation of certain elements were interpr eted in terms of kinetic and thermodynamic factors.