Ba2YCu3O(7-delta) - effect of oxygen stoichiometry

Samples prepared by Zr gettered annealing have been studied in order to investigate the effect of changes of oxygen stoichiometry on the properties of Ba2YCu3O(7-delta). Crystallographic, susceptibility, resisitivity, and specific heat results are presented for three different types of oxygen sites within a single a x a x 3a perovskite-crystallographic average cell. It is suggested that the local-moment formation in oxygen deficient materials is associated with a particular arrangement of oxygen and oxygen vacancies. Results support the possibility that a higher than four-fold oxygen coordination could lead to magnetic copper atoms. 17 references