LuBa2Cu3O7–x thin films prepared using MOCVD

Abstract

LuBa₂Cu₃O_7–x thin films with T_c= 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 j_c(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 |Δj_cΔT| for LuBa₂Cu₃O_7–x films on coherent substrates was found to be higher than that of YBa₂Cu₃O_7–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.