Influence of the buffer layer on the growth of superconducting films based onmercury

Abstract

Thin films of mercury based superconductors were prepared onR-planesapphire with a CeO2 buffer layer by a two-step process involving the deposition of the Hg-freeprecursor and ex situ mercuration in a sealed quartz tube. We usedCeO2 buffer layers of different thicknesses to study their influence on the phase composition andproperties of the final films. We succeeded in preparing a Hg-1223 superconducting phase on thinCeO2 buffered(10 nm) R-plane sapphire with a critical temperatureTC0 up to 122.5 K andcritical current density JC up to 4 × 105 A cm−2.