Liu, H. B. ; Morris, D. E. ; Jiang, X. P. ; Sinha, A. P. B. (1994) Silver raises the Tc of Pb-1212 to 78 K Physica C: Superconductivity, 222 (1-2). pp. 119-126. ISSN 0921-4534
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Official URL: http://www.sciencedirect.com/science/article/pii/0...
Related URL: http://dx.doi.org/10.1016/0921-4534(94)90122-8
Abstract
We report the first case of a substantial Tc enhancement in a cuprate superconductor by silver addition. The Tc enhancement has been observed in several Pb-1212 superconductors with the general formula (Pb0.5Cu0.5)Sr2(R1-xCax) Cu2O7 where R=Y, Gd, Dy, Ho, Er or Tm. The results are: (1) The highest Tc was 78 K for (Pb0.5Cu0.5)Sr2(Y0.5Ca0.5)Cu2O7. (2) Tc's were enhanced up to 15 K above those of the corresponding Ag-free samples. (3) The compounds with larger rare earths (and lower Tc) show the greatest Tcenhancement. (4) Tc enhancement increases with Ca content and is highest at x=0.5. (5) The Tc enhancement is larger with slower cooling rates. In fact, quenched samples (with Ag) showed a Tc depressed compared to similarly prepared silver-free samples. (6) EDX indicates that Ag enters the structure; the lattice parameters change with silver addition; the a-axis decreases by 0.15%, the c-axis increases by 0.5%. (7) Silver helps in oxygen transport thereby enabling an optimal oxygen content to be achieved.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to Elsevier Science. |
| ID Code: | 48959 |
| Deposited On: | 19 Jul 2011 07:27 |
| Last Modified: | 19 Jul 2011 07:27 |
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