Preparation of superconducting wire by deposition of YBa2Cu3Ox onto fibers

This paper reports on a controllable process developed for chemical vapor deposition of superconducting YBa2Cu3Ox. The process relies on feeding and transport of a finely ground powder mixture of Y, Ba, and Cu tetramethylheptanedionates into a CVD furnace. X-ray diffraction, scanning electron microscopy, analytical electron microscopy, resistance versus temperature, and critical current measurements have been used to characterize the films. The optimum processing parameters were determined using parametric studies involving temperature, pressure, reagent feed rate and composition, and coating time. Extensive c-axis orientation was observed using x-ray diffraction and transmission electron microscopy. The presence of impurity phases and substrate/coating interaction layers were observed. 2Cu3Ox coatings on MgO (100) single crystal substrates exhibited critical currents of 2 x 10 4 A/cm2 at 77 K, 0 Tesla, with critical temperatures (Resistance = 0) of 86 K. Deposition of the 2Cu3Ox materials onto several fibrous substrates has been achieved, and a continuous fiber coating furnace is in operation