Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-02T20:24:15.108Z Has data issue: false hasContentIssue false

Pb-doped Bi-2212: Homogeneity Area, Oxidation and Effect on jc

Published online by Cambridge University Press:  18 March 2011

A. Veresov
Affiliation:
Department of Materials Sciences, Moscow Sate University, Moscow 119899, RUSSIA Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
M. Pulkin
Affiliation:
Department of Materials Sciences, Moscow Sate University, Moscow 119899, RUSSIA
A. Knotko
Affiliation:
Department of Chemistry, Moscow Sate University, Moscow 119899, RUSSIA
V. Putlayev
Affiliation:
Department of Chemistry, Moscow Sate University, Moscow 119899, RUSSIA
E. K. H. Salje
Affiliation:
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
Get access

Abstract

The most promising way to improve jc in superconductors is likely to be a creation of small precipitates in the material during decomposition of supersaturated solid solution. It was recognised recently that Pb-doping of 2212 could have beneficial effect on jc. Bi2.1−xPbxSr2CaCu2O8+d (x=0.1…0.7) was prepared at different temperatures and oxygen partial pressure (pO2=10−3 – 0.21 atm) via nitrate route. The effect of pO2 and Pb-doping on Bi-2212 phase formation was explored with XRD, SEM/EPMA and TEM/SAED. The limit of Pb solubility in Bi-2212 was found to increase with a decrease in pO2 and corresponded to a decrease in x=0.3 at pO2 = 0.21 atm (850 °C) and x=0.6 at pO2 ∼ 10−3 atm (750 °C). TEM study of the as-synthesized solid solutions revealed significant nanoscale inhomogeneity attributed to Pb-segregation. For the samples with x > 0.3 the inhomogeneity quite often looked like a well- ordered wave with the period of about 10 nm. The samples of (Bi,Pb)-2212 processed under pO2 conditions were oxidized at 600–750°C in air for 0.5–60 h in order to cause precipitation of secondary phases from the supersaturated solid solution. Thermogravimetrical study (TG) of the oxidation gave a strong evidence of two stages composing the process. It was found that jc was enhanced by a factor of 2 after annealing at 650°C (i.e. during the first stage of oxidation).

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Majewski, P., Elschner, S., Aldinger, F., Physica C 249, 234 (1995).Google Scholar
2. Hiroi, Z., Chong, I., Takano, M., J. Solid State Chem. 138, 98110 (1998).Google Scholar
3. Shimoyama, J., Nakayama, Y., et al. , Physica C 281, 6975 (1997).Google Scholar
4. Crossley, A.L., Li, Y.H., Caplin, A.D., MacManus-Driscoll, J.L., Physica C 314, 1218 (1999).Google Scholar
5. Grivel, J.-C., Gladyshevskii, R.E., Walker, E., Flukiger, R., Physica C 274, 6672 (1997).Google Scholar
6. Shlichenmaier, M., Kemmler-Sack, S., Physica C 198, 175180 (1992).Google Scholar
7. Iwai, Y., Hoshi, Y., Saito, H., Takata, M., Physica C 170, 319324 (1990).Google Scholar
8. Jeremie, A., Alami-Yadri, K., Grivel, J.C., Flukiger, R., Supercond.Sci.Technol. 6, 730735 (1993).Google Scholar