Effect of Ag additions on shock wave degradation of superconductivity in BiPBSrCaCuO and YBaCuO

Abstract

While it has been successfully demonstrated that Bi-Pb-Sr-Ca-Cu-O and YBa{sub 2}Cu{sub 3}O{sub x} powders as well as mixtures of these powders along with silver and copper can be shock fabricated in metal or alloy matrices, it has been found that their superconducting properties are degraded by the shock wave. In shock fabricating Bi{sub 7}Pb{sub 3}Sr{sub 10}Ca{sub 10}Cu{sub 15}O{sub x}, it has been observed that at peak shock pressures of 4 GPa and above, the as-shocked material behaves as a semiconductor and there is no transition or superconducting onset in the resistance-temperature (R-T) signature. A transition was recently seen for the first time in Bi{sub 7}Pb{sub 3}Sr{sub 10}Ca{sub 10}Cu{sub 15}O{sub x} with plane wave shock loading at 1.5 GPa peak shock pressure. However, even at such a low peak pressure, the R-T signature showed signs of residual degradation: the normal state resistivity was semiconducting and it showed a two phase transition with a T{sub c}(R=O) of about 77 K. The R-T signatures of these degraded samples could, however, be completely recovered on proper heat treatment (typically around 860{degrees}C in flowing air for 90 hours). The results of the effect of the shock wave on Bi{sub 7}Pb{sub 3}Sr{sup 10}Ca{sub 10}Ci{sub 15}O{sub x}more » and YBa{sub 2}Cu{sub 3}O{sub x} at different Ag doping levels is presented in this paper.« less