Investigation of Y-Tb-Ba-Cu-O compounds by XPS

Composition and electronic structure of Y1-xTbxBa2Cu3O7-delta compounds are investigated using X-ray photoelectron spectroscopy. The complex Ba 3d and 0 ls core level photoelectron spectra at 0 less-than-or-equal-to x less-than-or-equal-to 1 are analysed. The additional peak attributed to peroxide ion O2(2-) species is found in O 1s spectra at x > 0. With increasing x a narrowing and a shift to lower energies are observed for the Ba 3d5/2 envelope peak. A break in the width of the Ba 3d peak as a function of x is found at x = 0.2, correlated with the start of the decomposition of the compound.