Microstructure and Interface Phase Formation in ${\rm YBa}_{2}{\rm Cu}_{3}{\rm O}_{7-\delta}$ Prepared by an MOD Process

Understanding the evolution of microstructure in YBCO (YBa
₂
Cu
₃
O
_7-zeta
) is critical to optimizing the process for production of high quality superconducting wire for commercial applications. Therefore, microstructure and interfaces have been investigated in fully reacted YBa
₂
Cu
₃
O
_7-zeta
, prepared by the metalorganic deposition (MOD) process, and deposited on CeO
₂
/YSZ/Y
₂
O
₃
/NiW. YBCO nucleates on CeO
₂
with a specific orientation relationship where [011] CeO
₂
|| [100] YBCO and (200) CeO
₂
|| (002) YBCO, and with the [001] YBCO axis parallel to the film growth direction. A 25-50 nm thick reaction layer of BaCeO
₃
was observed at the YBCO : CeO
₂
interface. Formation of this layer releases a considerable amount of Cu and Y into the YBCO matrix. Details of the interfacial phase formation in the MOD-processed YBCO films are presented in this paper.