Metallicity and positive magnetoresistance induced by Pb substitution in a misfit cobaltate crystal

Wataru Kobayashi, H. Muguerra, S. Hébert, D. Grebille, A. Maignan

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We have synthesized single crystals of the misfit-layered cobalt oxide, [Bi1.5Pb0.5Sr2O4-δ][CoO 2]1.86, with quadruple NaCl-type layers, using a flux method, and measured their transport properties. From structural refinements, it is found that the modulation in the BiO layer observed in [Bi 1.74Sr2O4-δ]RS[CoO 2]1.82 is suppressed by Pb substitution. The in-plane resistivity, thermopower, and Hall coefficient are 4.3 mΩcm, 101 νVK-1, and 1 × 10-2cm3C-1 at 300K, respectively; these are consistent with those of the misfit-layered cobalt oxides. All of these values are smaller than those of [Bi 1.74Sr2O4][CoO2]1.82, indicating that the carrier concentration is larger than that of the undoped crystal. Moreover, the low T upturn of resistivity observed for most of the cobalt misfit oxides is replaced by a metallic behavior, following a T 2 dependence, indicating strong correlations in the Pb-doped crystal. Also, the magnetoresistance, usually negative for misfit oxides, is replaced by a small positive magnetoresistance. Doping with Pb is thus an efficient way to suppress the low T localized behavior usually observed for misfits.

Original languageEnglish
Article number235404
JournalJournal of Physics Condensed Matter
Volume21
Issue number23
DOIs
Publication statusPublished - 2009
Externally publishedYes

Fingerprint

cobalt oxides
Magnetoresistance
metallicity
Substitution reactions
substitutes
Cobalt
Crystals
Oxides
crystals
electrical resistivity
Thermoelectric power
coefficients
doped crystals
Transport properties
Carrier concentration
Hall effect
transport properties
Doping (additives)
Modulation
Single crystals

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)

Cite this

Metallicity and positive magnetoresistance induced by Pb substitution in a misfit cobaltate crystal. / Kobayashi, Wataru; Muguerra, H.; Hébert, S.; Grebille, D.; Maignan, A.

In: Journal of Physics Condensed Matter, Vol. 21, No. 23, 235404, 2009.

Research output: Contribution to journalArticle

Kobayashi, Wataru ; Muguerra, H. ; Hébert, S. ; Grebille, D. ; Maignan, A. / Metallicity and positive magnetoresistance induced by Pb substitution in a misfit cobaltate crystal. In: Journal of Physics Condensed Matter. 2009 ; Vol. 21, No. 23.
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