NORMAL STATE RESISTIVITY IN EPITAXIALLY GROWN YBA2CU3OX THIN-FILMS WITH X = 6 TO 7

We have measured resistivity in the ab-plane (ρ{variant}ab) of epitaxially grown YBa2Cu3Ox thin films with an oxygen content (x) from 6 to 7. The superconducting thin films exhibit metallic behavior and nearly-linear dependence of ρ{variant}ab on T in normal state. The gradient of the ρ{variant}ab - T curves in normal state and the ρ{variant}ab at 280 K increases monotonically with decreasing x. These properties are very similar to those of La2-ySryCuO4 rather than YBa2Cu3Ox. We have pointed out that the hole doping into the Cu(2)O2 planes by oxygen in the Cu(1) planes can start from x slightly above 6.0 rather than 6.5. These observations are consistent with the argument that the conduction in both oxides is principally in the CuO2 planes. © 1990.