The interaction of Ag with Bi-Pb-Sr-Ca-Cu-O superconductor

✍ Scribed by S.X. Dou; K.H. Song; H.K. Liu; C.C. Sorrell; M.H. Apperley; A.J. Gouch; N. Savvides; D.W. Hensley

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 841 KB
• Volume: 160
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90431-0

✦ Synopsis

Sr-Ca-Cu-0 superconductor compounds have been doped with up to 30 wt% Ag, sintered under variable oxygen partial pressure, and characterised in terms of the electrical and crystallographic behaviour. In contrast to previous reports that claim that Ag is the only metal non-poisoning to the superconductivity of Bi-Sr-Ca-Cu-0

(BSCCO), it has been found that Ag additions to Bi-Pb-Sr-Ca-Cu-0 depress r, and J, drastically and cause a large decrease in lattice parameters when samples are treated in air or pure oxygen. However, the lattice parameters, r, and J, remain unaffected by Ag additions when samples are heat treated in 0.030-0.067 atm oxygen. It is clear that the Ag reacts with and destabilises the superconducting phase when the samples are treated in air or pure oxygen while, when the samples are heat treated in low oxygen partial pressures, the Ag remains as an isolated inert metal phase that improves the weak links between the grains. This discovery clearly shows the feasibility of Ag-clad superconductor wire. For Ag-clad superconductor tape of 0.1 mm2 cross sectional area heat treated in air, J, was measured to be 54 A/cmZ. The same specimen sintered in 0.067 atm oxygen showed that the .I, increased to 2078 A/cm'.