A study was made of interdiffusion at the interfaces of YBa2Cu3O7-x and metals, Au, Ag, and Pb by using X-ray reflectivity. The Cu3Ba2YO7 thin films were grown epitaxially by off-axis sputter deposition and co-evaporation, with the c-axis being perpendicular to the SrTiO3 substrate surfaces. The capping layers were subsequently deposited on the Cu3Ba2YO7 film in situ and ex situ near to room temperature. Glancing incident X-ray reflectivity was used to investigate the surfaces and their buried interfaces. It was found that interdiffusion at the interfaces of Au/Cu3Ba2YO7 and Ag/Cu3Ba2YO7 was negligible. However, a large interdiffusion zone of about 6nm was present at the Pb/Cu3Ba2YO7 interface and the Pb films grown, both in situ and ex situ, were entirely oxidized. No diffraction peaks from the Pb/Cu3Ba2YO7 films were observed. The diffraction peaks were found up to (007) from the Cu3Ba2YO7 films of the Au/Cu3Ba2YO7 and Ag/Cu3Ba2YO7 films. This implied that the loss of crystalline structure in a 30nm-thick Cu3Ba2YO7 film beneath Pb was caused by interdiffusion.

X-ray Reflectivity Study of Interdiffusion at YBa2Cu3O7-x and Metal Interfaces. S.W.Han, S.Tripathy, P.F.Miceli, E.Badica, M.Covington, L.H.Greene, M.Aprili: Japanese Journal of Applied Physics - 1, 2003, 42[3], 1395-9