XPS STUDY ON O(1S) ACID FE(2P) FOR NANOCRYSTALLINE COMPOSITE OXIDE LAFEO3 WITH THE PEROVSKITE STRUCTURE

The changes of the chemisorbed oxygen on the interface and surface of grains and the lattice oxygen in the bulk phase have been examined by the comparison of O(1s) spectra of several uncompacted and compacted m aterials LaFeO3 under the static pressures of 0.5, 1.0 and 1.5 GPa at ambient temperature. The results indicate that the amount of the chemi sorbed oxygen increases with the reduction in grain sizes, and it also changes with compacting pressures. When the diameters of grains reduc e to be less than 15 nm, the ratio of the chemisorbed oxygen to lattic e oxygen increases dramatically. It was found that the compacting pres sures also make Fe(2p) spectra change, and there are pseudozero valent iron atoms in nanocrystalline LaFeO3. These results reflect the diffe rences between nanocrystalline and conventional-crystal materials.