INFLUENCE OF CRITICAL PARAMETERS IN THE SYNTHESIS OF SUPERCONDUCTING THIN-FILMS OF YBA2CU3O7-X ON (100)SRTIO3 BY GLOW-DISCHARGE SPUTTERING

A systematic study on the influence of process parameters such as subs trate temperature, gas composition and ion current in the synthesis of superconducting thin films of YBa2Cu3O7-x, on(100) SrTiO3 by glow dis charge or high pressure sputtering is presented for the first time. Th is method offers a route to grow good quality thin films at substrate temperature as low as 923-933 K in a single uninterrupted cycle. Tile films grown at an optimum substrate temperature of 933 K and an ion cu rrent of 50 mA show a transition temperature at zero resistance of abo ut 87 K, a transition width of 1.5 K and critical current density of a bout 10(6) A.cm(-2) at 77 K, in zero magnetic field. These films show a characteristic basket weave microstructure, whereas the films grown at larger ion currents show an overgrowth morphology. An optimum oxyge n content in the argon-oxygen gas mixture ratio of 6 : 1 yields films of superior duality. The improvement in the superconducting properties of the films in relation to the quality of the target material used i s also discussed.