Comparison of carrier concentration determined by structural and electrical studies of cation substituted YSr2Cu3O7-δ

P. S I P N de Silva, T. G N Babu, C. Greaves, A. Jánossy, J. R. Cooper

Research output: Contribution to journalArticle

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Abstract

Results of resistivity (ρ{variant}(T)), thermoelectric-power (TEP) and magnetic-susceptibility (χ(T)) measurements are reported for Sr/Ba and Ca/Y substituted YBa2Cu3O7 (YBCO) with various substitutions (Co, Cr or Ga) on the Cu(1) chain site. From the TEP and the superconducting transition temperature (Tc) we conclude that Sr/Ba substitution decreases the carrier concentration of the Cr doped samples and seems to cause some pair breaking, and also that Ca substitution partially restores the hole density in agreement with the conclusions of Babu and Greaves [Physica C 207 (1993) 44]. Using the room-temperature TEP as a guide, we find that Cr doping causes less change in the carrier concentration than Co doping and suggest that its vortex pinning properties should be investigated. Resistivity and TEP for the Ga doped samples give evidence for a gap in the spin-excitation spectrum. This gap is not visible in the static susceptibility because of the presence of a significant Curie term, but electron spin resonance (ESR) measurements show that these spins are not from impurity phases. We propose that the unpaired spins form on the Cu(1) sites when the CuO chains are broken into short segments by Ga substitution.

Original languageEnglish
Pages (from-to)252-256
Number of pages5
JournalPhysica C: Superconductivity and its Applications
Volume243
Issue number3-4
DOIs
Publication statusPublished - Mar 1 1995

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Thermoelectric power
Carrier concentration
Cations
Substitution reactions
Positive ions
substitutes
cations
Doping (additives)
magnetic permeability
electrical resistivity
causes
Magnetic susceptibility
Superconducting transition temperature
Paramagnetic resonance
electron paramagnetic resonance
Vortex flow
transition temperature
vortices
Impurities
impurities

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Comparison of carrier concentration determined by structural and electrical studies of cation substituted YSr2Cu3O7-δ. / de Silva, P. S I P N; Babu, T. G N; Greaves, C.; Jánossy, A.; Cooper, J. R.

In: Physica C: Superconductivity and its Applications, Vol. 243, No. 3-4, 01.03.1995, p. 252-256.

Research output: Contribution to journalArticle

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