PROPERTIES AND MICROSTRUCTURES OF YBCO SUPERCONDUCTING TAPES PREPAREDON STATIC AND CONTINUOUSLY MOVING SILVER SUBSTRATES BY A NEW MOCVD REACTOR

We report the results on the preparation of YBCO superconducting tapes on silver substrates which are static and moving at a speed of 15 cm/ h, by means of a new MOCVD reactor. During deposition, the substrate t apes are heated at 845-855-degrees-C and kept in constant touch with t he fresh source gases, and the system pressure is kept at 0.67 KPa. Th e YBCO layers of the superconducting tapes consist of single-phase YBC O with a high degree of c-axis orientation normal to the substrates. T he FWHM of the X-ray rocking curve of the YBCO (005) peak is 3.8-degre es. The surface morphology looks smooth and dense for the statically d eposited sample, but not as well as for the dynamically deposited one. The J(c) values are 2.2 x 10(4) A/cm2 and 1.7 x 10(4) A/cm2 (78 K, 0 T) for the statically and dynamically deposited samples, respectively. The statically deposited sample has a zero resistance temperature of 88 K.