Microstructure analysis of GdBa2Cu3O7-δ coated conductors by the RCE-DR process

Abstract

ABSTRACTWe report the microstructural features of GdBa2Cu3O7-δ (GdBCO) coated conductors (CCs) on LaMnO3 (LMO)-buffered IBAD MgO template, produced by the Reactive Co-Evaporation Deposition & Reaction (RCE-DR) process. Analysis results by X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that a lot of elongated round second phase particles of 70-150nm size within the GdBCO matrix were the Gd2O3 phase, a small amount of Cu-O phase were also trapped in the GdBCO matrix, and a thick layer of Cu-excessive Ba-Cu-O phase was found on the top surface of the GdBCO film, suggesting that the GdBCO film might be grown from Gd2O3 and liquid phase by a peritectic recombination. While both the GdBCO film and some Gd2O3 particles grown on the LMO-buffer layer were biaxially textured, the Gd2O3 particles fully trapped in the GdBCO matrix were randomly oriented. The Gd2O3 particles located at the interface between the GdBCO and LMO buffer layer exhibited the following crystallographic orientation relationship: LMO [010] // GdBCO [010] // Gd2O3 [110]; LMO [001] // GdBCO [001] // Gd2O3 [001].