INFLUENCE OF WORKING GAS-PRESSURE ON THE PROPERTIES OF THIN-FILMS OF HIGH-TEMPERATURE SUPERCONDUCTORS OBTAINED BY MAGNETRON SPUTTERING

The surface morphology, composition, microstructure, and electrical pr operties of thin films of YBa2Cu3O7-x high-temperature superconductors , obtained by inverted magnetron sputtering, have been studied as a fu nction of the pressure of the working gas mixture and results are pres ented. The main parameters of the magnetron discharge plasma near the substrate were determined by analyzing the characteristics of Langmuir probes. Changes in the properties of the films are considered to be c aused by bombardment of the growing film with plasma ions accelerated in the floating potential field of the substrate. Films obtained at a pressure of 28 Pa and substrate temperature of 630 degrees C had a sup erconducting transition end temperature T-c,T- (off) = 89 K and a crit ical current density j(c) = 2 MA/cm(2) (at 77 K) and were free from se condary phase particles larger than 10 nm. (C) 1998 American Institute of Physics. [S1063-7850(98)03302-3].