XANES and wet-chemical analyses of the charge balance in (Hg,Pb)(Ba,Sr)2Ca2Cu3O8+z

T. Watanabe, N. Kiryakov, J. Poulsen, J. M. Lee, Jinming Chen, R. S. Liu, Hisao Yamauchi, M. Karppinen*

*Corresponding author for this work

Research output: Contribution to journalConference articleScientificpeer-review

4 Citations (Scopus)

Abstract

Here we present the results revealed from iodometric, coulometric and cerimetric titrations and Cu L-edge and O K-edge X-ray absorption near-edge structure analyses of the concentration and distribution of holes in a series of polycrystalline (Hg,Pb)(Ba,Sr)2Ca2Cu3O 8+z [(Hg,Pb)-1(Ba,Sr)223] samples. By means of oxygen-content tuning only, the average valence of copper in the pristine Hg-1(Ba)223 phase can be controlled in the range of 2.03-2.10. Substituting Hg partly with Pb increased considerably the amount of excess oxygen z in the (Hg,Pb)Oz charge-reservoir block. Lead was found to enter the phase with an oxidation state higher in average than III so as to increase the positive charge at the Hg site. However, the increase in the oxygen content counter-balanced the effect of higher-valent (Pb III/IV) for lower-valent (HgII) cation substitution such that the average CuO2-plane hole concentration was found higher for the (Hg,Pb)-1(Ba,Sr)223 sample with Tc = 115 K than for the optimally doped pristine Hg-1(Ba)223 sample with Tc = 134.5 K.

Original languageEnglish
Pages (from-to)93-98
Number of pages6
JournalPHYSICA C: SUPERCONDUCTIVITY AND ITS APPLICATIONS
Volume392-396
Issue numberPART 1
DOIs
Publication statusPublished - 1 Oct 2003
MoE publication typeA4 Article in a conference publication
EventInternational Symposium on Superconductivity - Yokohama, Japan
Duration: 11 Nov 200213 Nov 2002
Conference number: 15

Keywords

  • Hg-1223 superconductor
  • Hole-doping level
  • Metal valences
  • Wet-chemical redox analysis
  • XANES spectroscopy

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