Epitaxial growth of superconducting BaPb1−xBixO3 thin films

Abstract

Superconducting BaPb_1−xBi_xO₃ (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 T_c=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.