Effects of shock-modification on superconductivity in Tl2Ca2Ba2Cu3Oy and Bi2CaSr2Cu2Ox

Powder compacts of superconducting Tl2 Ca2 Ba2 Cu3 O sub y Tl-2223 and Bi2 CaSr2 Cu2 O sub x Bi-2122 were subjected to controlled, quantitative high-pressure shock-wave loading in gas-tight copper recovery capsules and preserved for post-shock analysis. Magnetization data show a substantial decrease in both diamagnetic shielding and Meissner effect for both compounds following shock modification over a range of peak pressures from 7.5 to 27 GPa and peak temperatures from 150 to 850 C. There is a 5 K increase in the onset of superconductivity in shock-modified Tl-2223, while Bi-2122 shows no measurable change. Magnetic flux creep measurements at low temperature reveal a three-fold increase in the flux pinning energy for Tl-2223 following shock modification.