Heat-treatment temperature/time and ambient effects on the properties of YBa2Cu3O7−x superconducting films derived from carboxylate precursors were investigated. The thin films were processed under O2, N2, or N2/O2 mixed atmosphere. The use of N2 or N2-rich atmosphere facilitated the 123 phase formation, grain growth, and orientation due to liquid phase assist sintering. Thin films with Tc(zero) = 87.8 and Jc > 105 A/cm2 at 77 K were prepared under such atmosphere at T ≤ 920 °C. Higher temperatures were required for thin films processed under O2 atmosphere and inferior transport properties were obtained. Processing above the melting temperature resulted in highly oriented films with dense microstructures and large grains, but significant post annealing was needed to obtain good film properties.
YBa2Cu3O7−δ superconducting films prepared by low pressure post-annealing