Sc. Tidrow et al., OXYGEN DIFFUSION THROUGH DIELECTRICS - A CRITICAL PARAMETER IN HIGH CRITICAL-TEMPERATURE SUPERCONDUCTORS MULTILAYER TECHNOLOGY, Journal of materials research, 10(7), 1995, pp. 1622-1634
We have studied the relative diffusion rates of oxygen through dielect
ric/buffer layers used in high critical temperature superconducting mu
ltilayer structures. Epitaxial bilayer films of dielectric (CeO2, LaGa
O3, NdGaO3, LaAlO3, MgO, SrTiO3, LaLiTi2O6, or LaNaTi2O6) on YBa2Cu3O7
-delta (YBCO) have been deposited onto (001) oriented single-crystal M
gO substrates using pulsed laser deposition, These bilayers have been
investigated for oxygen diffusion over the temperature range 350 to 65
0 degrees C by postdeposition annealing the films for 20 min in 0.5 at
m of O-18 enriched molecular oxygen gas. Secondary ion mass spectrosco
py was used to depth profile the relative concentration of O-18 to O-1
6 in each bilayer, Compared to YBCO, the dielectrics MgO, SrTiO3, LaLi
Ti2O6, and LaNaTi2O6 are relatively slow diffusers, while CeO2, LaGaO3
, NdGaO3, and LaAlO3 are relatively fast diffusers.