Bi-Sr-Ca-Cu-O HIGH-Tc SUPERCONDUCTORS PRODUCED BY USING A RAPID THERMAL MELT PROCESSING TECHNIQUE

• Published in: Journal of materials chemistry 1991-01, Vol.1 (1), p.97-102
• Main Authors: Moon, B M, Kordas, G
• Format: Article
• Language: English
• ISSN: 0959-9428
• DOI: 10.1039/jm9910100097

The conventionally sintered pellets were rapidly heat treated for 2 min at 1200 C at 1000 C/min and then annealed. The rapidly heat-treated samples exhibited non-superconducting crystalline phases which became superconducting upon annealing in air. A Tc(zero) of 105 K was obtained for the sample annealed at 861 C for 240 h. 30% Pb was substituted for Bi to stabilise the high-Tc (110 K) phase. Correlations between the processing conditions and the resulting properties of sintered and rapidly heat-treated samples were studied. Based on low-field magnetisation data, the low critical field of heat-treated samples was estimated to be 14% higher than that of the as-sintered samples. The bulk density increased by 10% after thermal heat treatments. In the rapidly heat-treated samples, 95% of the phases was estimated to be the high-Tc (2223) phase. X-ray analysis showed that the undesirable impurity phases were eliminated after heat treatment. Additionally, the effect of the magnetic field on the electrical resistance has been studied as a function of temperature, and Hall effect measurements have been carried out down to the superconducting state from pre-onset conditions to essentially zero resistance. 18 refs.