LuBa₂Cu₃O_7–xthin films prepared using MOCVD

Abstract

LuBa2Cu3O7–x thin films with Tc= 86–88 K were prepared by flash evaporation MOCVD on LaAlO3, SrTiO3, ZrO2(Y2O3) and NdGaO3 single-crystal substrates (deposition temperature 795 °C, partial oxygen pressure 1.35 Torr). Values for the critical current density jc(77 K., H= 100 Oe), of 9 × 105, 1.1 × 106 and 1.2 × 106 A cm–2 were measured for films on ZrO2(Y2O3), SrTiO3 and LaAlO3 respectively. The calculated magnitude of |ΔjcΔT| for LuBa2Cu3O7–x films on coherent substrates was found to be higher than that of YBa2Cu3O7–x films, indicating a more efficient magnetic flux pinning mechanism. The temperature dependence of conductivity fluctuations was considered in terms of a Lawrence–Donniach model and a 3D → 2D dimensional crossover was registered for the films on SrTiO3.