METALORGANIC CHEMICAL-VAPOR-DEPOSITION OF HIGH-QUALITY LUBA2CU3O7-DELTA THIN-FILMS - PECULIARITIES OF GROWTH AND SUPERCONDUCTING PROPERTIES

Epitaxial LuBa2Cu3O7-delta films were prepared by Bash evaporation met alorganic chemical vapour deposition (MOCVD) on LaAlO3, SrTiO3 and ZrO 2(Y2O3) substrates. The highest T-c and j(c) (77 K, 100 Oe) values ach ieved were 89 K, 2.7.10(6) A cm(-2), 88 K, 1.5.10(6) A cm(-2) and 87 K , 1.0.10(6) A cm, respectively. An influence of p(O-2) (at the deposit ion temperature T=800 degrees C) on structural and superconducting cha racteristics of LuBa2Cu3O7-delta films was found to be similar to that in the case of YBa2Cu3O7-delta, in spite of the difference in morphol ogy features and j(c)(T) dependencies. Occurrence of secondary phases inclusions in LuBa2Cu3O7-delta films was analysed by XRD and TEM. The ''fully oxygenated'' LuBa2Cu3O7 was found to be overdoped; an increase of T-c value by 3 K was observed after an annealing of the films at r educed p(O-2).