Microstructure modification of La2Zr2O7 buffer films for coated conductors by metal organic decomposition

Abstract

La2Zr2O7 (LZO) film directly deposited on Ni-5 at.%W by a chemical solution technique, metal organic decomposition (MOD), indicated a poor texture characteristic, which would result in high-angle grain boundaries in subsequent YBa2Cu3O7−δ (YBCO) associated with weak-link behavior. Different ultrathin MOD-LZO, Y2O3, and CeO2 seed layers (~several nanometers) with various annealing temperature were inserted to improve the crystallographic alignment. The relation between the texture and annealing temperature was systematically investigated. A CeO2 seed layer allows us to grow high quality LZO epitaxial films with values of full width at half-maximum around 5.61° and 5.13° for the Φ-scan of (222) and rocking curve of (400) LZO, respectively, which is comparable to the microstructure of films grown using physical vapor deposited Y2O3 as a seed layer. This buffer template, serving for YBCO coated conductors, could potentially decrease the overall fabrication cost.