SUPERCONDUCTING PROPERTIES OF OXYGEN-DEFICIENT LUBA2CU3O7 THIN-FILMS

An increase of more than 3 K of the T-c value was observed for LuBa2Cu 3O7-x epitaxial films, being at first fully oxygenated, after annealin g at reduced oxygen partial pressure (0.05-0.3 bar). The effect is rel ated to the optimization of the hole concentration in the Cu(2)O-2 pla nes. The dependence of the normal state electrical conductivity at 390 K on the oxygen partial pressure was found to be linear with the slop e coefficient 0.17 in logarithmic coordinates. The oxygen stoichiometr y (7 - x), estimated from conductivity measurements, and the lattice p arameter c of LuBa2Cu3O7-x films correlate satisfactorily with the c(x ) variation for YBa2Cu3O7-x. The temperature dependence of the critica l current density in LuBa2Cu3O7-x epitaxial films is rather insensitiv e to the variation of oxygen content in the 0.02 < x < 0.27 interval.