Microstructural Observation of YBCO Superconducting Tape with Textured Cu Substrate

Abstract

The microstructure of YBa₂Cu₃O_7-δ (YBCO) superconducting wire with textured Cu substrate was investigated using an electron back scattering pattern (EBSP) and transmission electron microscopy (TEM). The structure of this wire is YBCO/CeO₂/YSZ/CeO₂/electro-plated Ni/textured Cu/SS. The YBCO film with J_c of 3.2 MA/cm² was prepared for this observation. The crystallographic orientation relationship between the Ni layer and the Cu layer was investigated. The good cube-on-cube epitaxy including the position and the direction of the grain boundaries were confirmed. In addition, the clear layered structure and fact that there were no out-of-phase components were confirmed. From the electron beam diffraction, the crystallographic orientation relationship was confirmed as YBCO(006)//CeO₂(002)//YSZ(002)//CeO₂(002)//Ni(002) and YBCO(200)//CeO₂(220)//YSZ(220)//CeO₂(220)//Ni(200). From the results of energy dispersive X-ray spectrometry (EDS), the diffusion of Ni and Cu were confirmed. The need to optimize the Ni-layer thickness was suggested.