XPS Studies of 80 K-Phase Bi-Sr-Ca-Cu-O Single Crystals

Abstract

The XPS (X-ray photoelectron spectroscopy) measurements of the 80 K-phase Bi-Sr-Ca-Cu-O single crystals were carried out on surfaces obtained by cleaving in vacuum, by cleaving in air and heating in vacuum, and by Ar + -sputter etching of the air-cleaved-and-heated surface. The chemical bond natures of all the constituent elements from the air-cleaved-and-heated surface are approximately equal to those from the vacuum-cleaved surface. Sr and Ca from the sputtered surface are more oxidized than those from the vacuum-cleaved surface.