Oxygen nonstoichiometry and high temperature conductivity of the 2201 phase of the Bi-Sr-Cu-O superconducting oxide

The oxygen nonstoichiometry and high temperature conductivity of Bi2.12Sr1.86Cu1.02Oy (2201 phase) were determined as a function of temperature (T) and oxygen partial pressure (PO2). The dependences of conductivity on T and PO2 were similar to those of oxygen content, and two subphases, α and β, were found in such cases as 2212 and 2223 phases. From the results a close relationship was inferred between conductivity and oxygen content, and the mobility and carrier density were calculated. The carrier density of 2201 phase was smaller than those of the 2212 and 2223 phases. (orig.)