Technical Report of Issp. Ser. A, No. 2669: Relations Between Oxygen Deficiencyand Structures in the La-Sr-Cu-O System. 3: Oxygen Contents and Structure of (La, Sr)8Cu8O(16+delta) Phase

摘要

The oxygen content of (La(1-x)Sr(x))8Cu8O(16 + delta) was determined forvariously heat-treated samples. It increases with increasing partial pressure of oxygen, for example, x = 0.75 and delta = 0.08 (annealed in Ar at 810 C), 0.27 (quenched from 1050 C in air), 2.29 (annealed in O2 at 800 C), and 2.54 (treated under O2 high-pressure 300 atm). X-ray diffraction studies indicate that there are two distinct phases, the oxygen-poor phase (delta approx. = 0.0--the 8-8-16 phase) and the oxygen-rich phase (delta greater than or equal to 2.0--the 8-8-18 phase).