X-RAY PHOTOELECTRON STUDIES OF COPPER AND OXYGEN STATES IN HIGH-T(C) SUPERCONDUCTING CUPRATES

XPS study has been carried out for La1.8Sr0.2CuO4-delta' T(C) = 37K; Y Ba2Cu3O6.9, T(C) = 95K; Bi2Sr2CaCu2O8+DELTA, T(C) = 85K; Tl2Ba2CaCu2O8 +DELTA, T(C) = 103 K and all initial oxides. It has been found that O1 s electron binding energies of oxygen ions on inequivalent lattice sit es in the cuprates were within about 1 eV. Oxidation degree of copper ions in the cuprates was close to that in CuO, while O1s electron bind ing energies of oxygen ions within Cu-O plane of the cuprates were les s about 1 eV than that in CuO. In the cuprates relative to CuO weighte d average binding energies of Cu3d electrons were unchanged, but weigh ted average binding energies of O2p electrons from oxygens within copp er planes decreased about 1 eV moving closer to the energy of Cu3d ele ctrons.