The relationship between nano-scale Sm211/Sm123 interfaces and superconductivity of Sm-Ba-Cu-O materials

The distribution of dislocations at the interface between the Sm₂BaCuO₅ particles (Sm211-particles) and SmBa₂Cu₃O₇ (Sm123) matrix with different 211-particle size from μm to nm was measured. It is found that the density of dislocations varies with the different curvatures of the 211-particles. There is a higher density of dislocations around small-sized 211-particles, especially those with sharp corners, which act as pinning centers and thus enhance the J_c(H,T) values of the superconductors. A phenomenological model has been proposed to describe the relationship between the curvature of 211-particles, the dislocation density around 211/123 interface, as well as the J_c(H,T).