GRAIN-ORIENTATION OF THE YBA2CU3OY SUPERCONDUCTING THIN-FILMS PREPARED BY THE LOW-PRESSURE PLASMA FLASH EVAPORATION TECHNIQUE AND ITS DEPENDENCE ON THE STARTING COMPOSITION

We have prepared superconducting thin films on MgO(100) substrates by a deposition technique using low pressure plasma flash evaporation. Th e r.f. plasma was sustained under 20 Torr by a 13.56 MHz r.f. generato r operated at 8 kW. The films show various grain orientations dependin g on the conditions of deposition. With some modifications in the star ting material composition, superconducting properties of the best film achieved were T(c) (resistivity rho = 0) = 90 K and J(c) (at 77 K and zero field) = 1.7 x 10(5) A cm2.