Epitaxial growth of superconducting BaPb1−xBixO3 thin films

Superconducting BaPb1−xBixO3 (BPB) thin films have been epitaxially grown on sapphire (011̄2) and SrTiO3 (100) single-crystal substrates at around 700 °C by the planar rf magnetron sputtering method, under relatively high pressure Ar-O2 mixed gas atmosphere. As-sputtered BPB films on SrTiO3 (100) exhibit superconductivity with a sharp transition at Tc=10 K. The resistivity, 8×10−4 Ω cm, is more than one order of magnitude smaller, and the critical current, 2.5×105 A/cm2, is more than two orders of magnitude larger than those reported earlier. The Hall mobility is 3.0 cm2/V s. The films are confirmed to be single crystals directly by the absence of grain boundary Josephson junctions, which polycrystalline BPB inherently possesses, as well as by the x-ray diffraction and the reflection electron diffraction analysis.