Visualizing extended defects at the atomic level in a Bi2Sr2CaCu2O8+δ superconducting wire

Abstract

The microstructure significantly influences the superconducting properties. Herein, the defect structures and atomic arrangements in high-temperature Bi2Sr2CaCu2O8+δ (Bi-2212) superconducting wire are directly characterized via state-of-the-art scanning transmission electron microscopy. Interstitial oxygen atoms are observed in both the charge reservoir layers and grain boundaries in the doped superconductor. Inclusion phases with varied numbers of CuO2 layers are found, and twist interfaces with different angles are identified. This study provides insights into the structures of Bi-2212 wire and lays the groundwork for guiding the design of microstructures and optimizing production methods to enhance superconducting performance.