High pressure synthesis and structure of the superconducting mercury cuprates (Hg1-xMx)Ba2Can-1Cu nO2+2n+∂ with M= C, S

P. Bordet, S. Loureiro, S. LeFloch, J. J. Capponi, C. Chaillout, J. Chenavas, J. L. Tholence, E. V. Antipov, P. G. Radaelli, M. Marezio

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In mercury superconducting cuprates synthesized at high pressure, partial carbon substitution on the mercury site occurs when the precursors are not absolutely carbon free. Hg-12(n-1)n samples made from carbonate-containing precursors show lower Tcs and smaller c parameter. A model of the structural arrangement of the CO3-2 groups is proposed from neutron diffraction data and crystal-chemistry considerations. The third oxygen of the oxyanion is situated in the (Hg,C)O layer and hinders the incorporation of extra-oxygen atoms. The (Hg1-xCx)Ba2CuO4+∂ phase diagram shows three different phases, namely HgBa2CuO4+∂, Hg0.5C0.5Ba2CuO4+∂ and CBa2CuO4+∂. The latter two phases are not superconducting due to the insufficient hole concentration on the superconducting layer. Sulphur can also partially replace mercury in Hg1-xSxBa2CuO4+∂ and forms a solid solution up to x=0.15. Neutron diffraction shows that the sulphur atoms arrange as S04-2 oxyanions. The larger S-O distances induce steric limitations to the presence of other sulphate anions in the same mesh.

Original languageEnglish
Pages (from-to)65-68
Number of pages4
JournalPhysica C: Superconductivity and its Applications
Volume282-287
Issue numberPART 1
DOIs
Publication statusPublished - Aug 1997
Externally publishedYes

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