Phase stability limits of Bi2Sr2Ca1Cu2O8+δ and Bi2Sr2Ca2Cu3O10+δ

Abstract
We determined the phase stability limits of Bi2Sr2Ca1Cu2O8+δ and Bi2Sr2Ca2Cu3O10+δ in the temperature range 650–880 °C using a solid‐state electrochemical technique. These phases decompose by incongruent melting above ∼790 °C, whereas they decompose by a solid‐state reaction at lower temperatures. The solid‐state decomposition reaction is reversible for Bi2Sr2Ca1Cu2O8+δ, but not for Bi2Sr2Ca2Cu3O10+δ.