Fabrication of stable superconductive wires with YBa2Cu3Ox/Ag2O composite core

1077-3118

AIP Digital Archive

Physics

The problem of maintaining the oxygen stoichiometry of the Y1Ba2Cu3Ox (the so-called 123) compound at the desired level of x=6.0±0.1 when fabricating superconducting wires using the powder-in-tube method is addressed. A solution to this problem appears to be incorporating an unstable oxide like Ag2O in the core material, such that it acts as an in situ oxygen donor during the final sintering or annealing stage. Moreover, the segregation of Ag at the grain boundaries of the 123 grains and at the porosities seems to be a possible reason for the considerable improvement of the critical current density Jc of these wires. The effect of processing parameters, like different sintering temperatures and addition of various percentages of either Ag or Ag2O, is presented. Finally, in order to test conservation of superconductive properties during handling, the wires were subjected to different degrees of bending, and the subsequent effect on superconducting transition temperature, Tc and Jc, is reported.

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