Atomic interface sequence, misfit strain relaxation and intrinsic flux-pinning defects in different YBa2Cu3O7-delta heterogeneous systems

作者：Zhu Yuanyuan^*; Tsai Chen Fong; Wang Haiyan

来源：Superconductor Science and Technology, 2013, 26(2): 025009.

DOI：10.1088/0953-2048/26/2/025009

To explore the interface effects on enhancing critical current density in YBa2Cu3O7-delta (YBCO) thin films, four heterogeneous systems, of which two have small opposite lattice misfits (i.e., the YBCO/STO (similar to 1.6%) and the YBCO/LAO (similar to-1.6%)), and the other two have relatively large opposite mismatch (i.e., the YBCO/MgO (similar to 8.9%) and the YBCO/YSZ (similar to-5.9%)), were selected and synthesized by pulsed-laser deposition. A detailed microstructure analysis including XRD, TEM and the state-of-the-art Cs-corrected STEM imaging, and a thorough superconducting property characterization including critical transition temperature (T-c) and critical current density (J(c)(self-field) and J(c)(in-field) (H parallel to c) at various temperatures), were conducted for all four heterogeneous systems. The results reveal that the YBCO intrinsic defects, driven by the interface mismatch of different strain states, present a diverse nature in their distribution and density, and thus different flux-pinning performances under various measurement conditions. This study provides an in-depth insight into the microstructure-property correlation in a strongly correlated electronic system, the YBCO heterogeneous structures.

• 出版日期2013-2