Variation of La 3 d photoelectron spectra of La 1.9Sr 1.1− xCa xCu 2O 6+ δ

Abstract

X-ray photoelectron spectra for La 3 d core-level region were measured to discuss the effect of cation substitution on electronic state of a cation substituted system of La 1.9Sr 1.1− x Ca x Cu 2O 6+ δ . Content of oxygen decreased with the increase of Ca content, x. Relative intensity ratio for the main (|3 d 94 f 0>) peak ( I M) to satellite (|3 d 94 f 1 L >) peak ( I S) in La 3 d region decreased with the increase of Ca content, even though the averaged interatomic distance between La and oxide ion was kept almost constant. It was found that the variation of I M/ I S ratio corresponded to variation of oxygen content, δ. It was concluded that the variation of I M/ I S with Ca content was due to the change in hole concentration in oxygen site.