Nanoscale Analysis of Interface Structure and Related Strain of Bi2sr2cacu2o8+ Δ /Laalo3 Heterogeneous System

Abstract

In view of the fact that interface structure and strain have significant effects on the performance of superconducting films with heterogeneous structures, the interface structure and strain of the Bi2Sr2CaCu2O8+ δ superconducting thin film fabricated with the sol-gel technique were investigated by aberration-corrected HAADF-STEM, EDX and GPA. The results revealed that the interfacial atomic sequence was LaAlO3(AlO2 terminated)-SrO-(Bi2212) n , where the -SrO- layer was the nucleation layer, and (Bi2212) n included intergrowth the phase of Bi2201, Bi2212 and Bi2223 . Through the combined effect of the several lattice mismatch relaxation methods such as lattice distortion and stacking fault, the final Bi2212 film undergoes an average in-plane compressive strain (εxx ~ -0.4501%) compared with bulk Bi2212. In addition, in-plane compressive strain related to the structure of the Bi2212/LaAlO3 heterostructure, gradually released as the distance away from the heterointerface increased.

Keywords: Bi2212 Superconducting Thin Film, Interface Structure, Microstructure, Domain Matching Epitaxy, Compressive strain