Abstract: The core levels and valence band spectra of LnCu2O4(Ln=Gd, Nd) were recorded by XPS. It has been observed that the Ln 3d binding energies of LnCu2O4 are 0.8－0.9 eV lower than that of the corresponding rare earth oxide. On the other hand, the Cu 2p binding energies of LnCu2O4 are 0.4－0.5 eV higher than that of CuO. This has been explained by the Cu→O→Ln charge transfer in Ln－O－Cu linkage of LnCu2O4. The XPS results also show that there is no mixed valence of Cu in LnCu2O4. The Xray induced valence bands reveal that the center of Ln 4fCu 3dO 2p valence band for Nd0.97Cu2O4 has a 3.4 eV lower binding energy compared to the center for Gd0.98Cu2O4. Besides, the width of valence band for Nd0.97Cu2O4 is narrower than that of Gd0.98Cu2O4.

Key words: LnCu₂O₄(Ln=Gd, Nd), Complex oxides, Electronic structure, XPS