High quality twin-free c-axis oriented YBa2Cu3O7 films were grown by pulsed laser deposition on NdGaO3. We find resistive anisotropies between 1 < a/b < 1.6. The resistive anisotropy above Tc appears to be correlated to the anisotropy in the critical current below Tc. The normal state properties of the chains along b seem to have a significant influence on the superconducting properties of YBa2Cu3O7.
Dam, B., Rector, J., Surdeanu, R., Wijngaarden, R. J., Koster, G., Peerdeman, F., ... Griessen, R. (1998). The ab-anisotropy of twinfree YBa2Cu3O7-delta above and below Tc. Physica C, C282(c287), 665-666. https://doi.org/10.1016/S0921-4534(97)00482-6