Growth and superconducting transition of Pr1−xCaxBa2Cu3O7−δ(x ≈0.5) epitaxial thin films

Pr1−xCaxBa2Cu3O7−δ(x ≈0.5) thin films have been grown on SrTiO3 and YSZ substrates by the pulsed laser ablation. The substrate temperature dependence of orientation and superconducting poperties were systematically studied. Good quality c and a-axis orientated films can be obtained on SrTiO3 via changing the substrate temperature solely. On YSZ, films with good c-axis orientation can be grown, while it is hard to grow films with good a-axis orientation by changing substrate temperature alone. The highest TC0 is about 37K, which is found in the films grown on YSZ with a good c-axis orientation. For the films grown on STO, however, the highest TC0 is about 35.6K with a mixed orientation of c-axis and a-axis. In most of the superconducting films, the weak temperature dependence of the normal state resistivity, as characterized by small R(290K)/R(50K)≤ 2 ratios, together with a weak localization behavior just above TC could be attributed to the essential scattering due to the localized electronic states. The superconducting transitions in a field up to 10 T along c-axis have been measured on a c-axis oriented film grown on SrTiO3. The zero-temperature in-plane upper critical field B C2 (0) is estimated from the resistivity transition data. PACS numbers: 81.15.Gh, 68.55.-a, 74.78.Bz, 74.72.-h Submitted to: Supercond. Sci. Technol. § To whom correspondence should be addressed (e-mail: [email protected]) Growth and superconducting transition of Pr1−xCaxBa2Cu3O7−δ(x ≈0.5) epitaxial thin films2