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 Bi 2 Sr 2 CaCu 2 O 8+ 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 CuO 2 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 the production methods to enhance superconducting performance.