Progress in the Study of Vortex Pinning Centers in High-Temperature Superconducting Films

Enhanced critical current density in optimized high-temperature superconducting bilayer thin films

The superconducting and structural properties of bilayer thin films based on YBa2Cu3O7-x / YBa2Cu3O7-x+6%BaZrO3heterstructures have been studied. In a broad range of magnetic field strengths and temperatures, the optimal bilayer film comprises 30% YBCO at the substrate interface and 70% YBCO+6%BZO on the top. The critical current density measured for the optimal bilayer structure is shown to outperform the corresponding single layer films up to almost 60%. The obtained results are comprehensively discussed in the light of our previously published theoretical framework (Rivastoet al2023J. Phys.: Condens. Matter35075701:1-10). We conclude that the bilayering provides an efficient and easily applicable way to further increase the performance and applicability of high-temperature superconductors in various applications. Consequently, the bilayer films should be seriously considered as candidates for the upcoming generation of coated conductors.

Effect of Er/Y addition on the growth and superconductivity of Bi2212 films

In order to increase the critical current density of Bi2212 superconducting films to broaden their application areas. A series of Bi₂Sr₂CaCu₂O_8+δ-xRE₂O₃ (RE = Er/Y) (x = 0, 0.04, 0.08, 0.12, 0.16, 0.20) thin films were prepared by the sol-gel method. The structure, morphology and superconductivity of the RE₂O₃ doping films were characterized in detail. The effect of RE₂O₃ on the superconductivity of Bi2212 superconducting films was investigated. It was shown that the Bi2212 films were (00l) epitaxially grown. The in-plane orientation relationship between the Bi2212-xRE₂O₃ and the SrTiO₃ was Bi2212[100](001)//SrTiO₃[011](100). The grain size in the out-of-plane direction of Bi2212 tends to increase with the amount of RE₂O₃ doping. Doping with RE₂O₃ had no significant effect on the anisotropy of Bi2212 crystal growth, but inhibited the agglomerative growth of the precipitated phase on the surface to a certain extent. Furthermore, the conclusion was that the superconducting transition temperature (T_c,onset) was almost unaffected, while the zero resistance transition temperature (T_c,zero) continued to decrease with increasing doping level. The thin film samples Er2 (x = 0.04) and Y3 (x = 0.08) exhibited the best current-carrying capacity in magnetic fields.