Effect of sodium substitution on superconductivity in Bi-based (2212) system

✍ Scribed by B. Gopala Krishna; Ravichandra Gundakaram; S.V. Suryanarayana; R.D.K. Misra

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 612 KB
• Volume: 200
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90397-u

✦ Synopsis

Samples with the nominal composition

BizSrzCa,_,Na,CuzO, (with x=0.05,0.2,0.4 and 0.5) were prepared by the solid state reaction method. The role of Na and the effect of various heat treatments in the 2212 composition were studied. From the X-ray diffraction data it is found that the samples annealed for longer duration have shown a single phase 2212. From the DC fourprobe resistivity data, it was found that the T,(zero) varies from 79 to 89 K. It is believed that doping with an alkali element would reduce the oxygen content due to monovalency and gives an effect similar to that during heat treatment under low oxygen pressure or quenching. The presence of sodium in the samples was confirmed by electron probe microanalysis.