Electron microscopy on the Tc = 110 K (midpoint) phase in the system Bi2O3–SrO–CaO–CuO

Abstract

The system is known to have at least two phases exhibiting high superconducting transition temperatures (TC) of 85 and 110 K. It is well established that Bi2Sr2CaCu2O8+δ has a TC of ~85 K. To date it is not known which phase in the system exhibits TC = 110 K. We performed high-resolution electron microscopy and analytical electron microscopy on material having a nominal composition BiSrCaCu2Ox, and containing a relatively high fraction of the phase with TC = 110 K. Two structures related to the structure of Bi2Sr2CaCu2O8+δ are found. These structures and their possible compositions are discussed.