The Effects of Grain Boundaries on the Current Transport Properties in YBCO-Coated Conductors

Nanoscale Res Lett. 2015 Dec;10(1):416. doi: 10.1186/s11671-015-1124-8. Epub 2015 Oct 26.

Abstract

We report a detailed study of the grain orientations and grain boundary (GB) networks in Y2O3 films grown on Ni-5 at.%W substrates. Electron back scatter diffraction (EBSD) exhibited different GB misorientation angle distributions, strongly decided by Y2O3 films with different textures. The subsequent yttria-stabilized zirconia (YSZ) barrier and CeO2 cap layer were deposited on Y2O3 layers by radio frequency sputtering, and YBa2Cu3O7-δ (YBCO) films were deposited by pulsed laser deposition. For explicating the effects of the grain boundaries on the current carry capacity of YBCO films, a percolation model was proposed to calculate the critical current density (J c) which depended on different GB misorientation angle distributions. The significantly higher J c for the sample with sharper texture is believed to be attributed to improved GB misorientation angle distributions.

Keywords: Current carry capacity; Grain boundary (GB); Misorientation angles; YBa2Cu3O7-δ (YBCO).