Characterisation of the spinels MxCo1−xFe2O4 (M = Mn, Fe or Ni) using X-ray photoelectron spectroscopy

X-ray photoelectron spectra have been recorded from a series of characterised cobalt-iron containing spinels MxCo1−xFe2O4 where M = Mn, Fe or Ni and 0 ≤ x ≤ 1. The binding energies of photoelectron peaks observed for the transition metal ions were recorded. Changes in their relative positions were noted and the measured intensities used to determine the surface composition. The observed surface segregation of certain elements were interpreted in terms of kinetic and thermodynamic factors.