Multi-step process to prepare bulk BSCCO (2223) superconductor with improved transport properties

Anna Tampieri, G. Calestani, G. Celotti, R. Masini, S. Lesca

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

BSCCO (2223) superconducting powders were prepared by three different techniques (solid state, pyrolysis and sol-gel) and with three different stoichiometries, especially based on variations of Ca/Sr ratio and Cu concentration. Pressureless sintering was performed on cold uniaxially pressed (1 GPa) samples, avoiding the drawbacks connected to hot-pressing; different hot-forging cycles were then applied to attain higher density and orientation factor. It was found that the process phenomenology is strictly linked to the powder starting stoichiometry: when composition is very near to the theoretical (2223), effects of secondary phase extrusion are observed during hot-forging, yielding a purification and inhibition of (2212) formation accompanied by an appreciable increase of Jc respect to hot-pressed samples. When a Ca/Sr ratio is considerably > 1, recrystallisation of (2223) from the liquid takes place, with a remarkable improvement of critical current density (Jc > 104 A/cm2). In this case the non-superconducting secondary phases act as intrinsic oxygen reservoir. Finally, when composition diverges even more from (2223) (Ca/Sr ≫ 1 and Cu excess), the formation of too many precipitates of non-superconducting phases hinders the texturing process and more in general deteriorates the intergranular properties.

Original languageEnglish (US)
Pages (from-to)21-33
Number of pages13
JournalPhysica C: Superconductivity and its Applications
Volume306
Issue number1-2
DOIs
StatePublished - Sep 10 1998

Keywords

  • BSCCO (2223) superconductor
  • Pyrolysis
  • Sol-gel
  • Solid state

ASJC Scopus subject areas

  • Condensed Matter Physics

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