LUBA2CU3O7-X THIN-FILMS PREPARED USING MOCVD

LuBa2Cu3O7-x thin films with T-c=86-88 K were prepared by flash evapor ation MOCVD on LaAlO3, SrTiO3, ZrO2(Y2O3) and NdGaO3 single-crystal su bstrates (deposition temperature 795 degrees C, partial oxygen pressur e 1.35 Torr). Values for the critical current density,j(c) (77 K, H = 100 Oe), of 9 x 10(5), 1.1 x 10(6) and 1.2 x 10(6) A cm(-2) were measu red for films on ZrO2(Y2O3), SrTiO3 and LaAlO3 respectively. The calcu lated magnitude of \Delta j(c)/Delta T\ for LuBa2Cu3O7-x films on cohe rent substrates was found to be higher than that of YBa2Cu3O7-x films, indicating a more efficient magnetic flux pinning mechanism. The temp erature dependence of conductivity fluctuations was considered in term s of a Lawrence-Donniach model and a 3D-->2D dimensional crossover was registered for the films on SrTiO3.