Na content dependence of superconductivity and the spin correlations in NaxCoO2·1.3H2O

Guo-Qing Zheng, Kazuaki Matano, R. L. Meng, J. Cmaidalka, C. W. Chu

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

We report systematic measurements using the 59Co nuclear quadrupole resonance (NQR) technique on the cobalt oxide superconductors Na xCoO2·1.3H2O over a wide Na content range x ≤ 0.25-0.34. We find that Tc increases with decreasing x but reaches a plateau for x≤0.28. In the sample with x∼0.26, the spin-lattice relaxation rate 1/T1 shows a T3 variation below Tc and down to T∼Tc/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x,1/T1 deviates from the T3 variation below T∼2 K even though the Tc (∼4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wavevector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.

Original languageEnglish
JournalJournal of Physics Condensed Matter
Volume18
Issue number5
DOIs
Publication statusPublished - Feb 8 2006

Fingerprint

Nuclear quadrupole resonance
Oxide superconductors
Spin-lattice relaxation
Superconductivity
Fermi level
Cobalt
superconductivity
cobalt oxides
nuclear quadrupole resonance
spin-lattice relaxation
plateaus
orbitals
cobalt oxide

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Na content dependence of superconductivity and the spin correlations in NaxCoO2·1.3H2O. / Zheng, Guo-Qing; Matano, Kazuaki; Meng, R. L.; Cmaidalka, J.; Chu, C. W.

In: Journal of Physics Condensed Matter, Vol. 18, No. 5, 08.02.2006.

Research output: Contribution to journalArticle

@article{567019e6d5e14dd3a49aebfdbda7e9f8,
title = "Na content dependence of superconductivity and the spin correlations in NaxCoO2·1.3H2O",
abstract = "We report systematic measurements using the 59Co nuclear quadrupole resonance (NQR) technique on the cobalt oxide superconductors Na xCoO2·1.3H2O over a wide Na content range x ≤ 0.25-0.34. We find that Tc increases with decreasing x but reaches a plateau for x≤0.28. In the sample with x∼0.26, the spin-lattice relaxation rate 1/T1 shows a T3 variation below Tc and down to T∼Tc/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x,1/T1 deviates from the T3 variation below T∼2 K even though the Tc (∼4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wavevector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.",
author = "Guo-Qing Zheng and Kazuaki Matano and Meng, {R. L.} and J. Cmaidalka and Chu, {C. W.}",
year = "2006",
month = "2",
day = "8",
doi = "10.1088/0953-8984/18/5/L02",
language = "English",
volume = "18",
journal = "Journal of Physics Condensed Matter",
issn = "0953-8984",
publisher = "IOP Publishing Ltd.",
number = "5",

}

TY - JOUR

T1 - Na content dependence of superconductivity and the spin correlations in NaxCoO2·1.3H2O

AU - Zheng, Guo-Qing

AU - Matano, Kazuaki

AU - Meng, R. L.

AU - Cmaidalka, J.

AU - Chu, C. W.

PY - 2006/2/8

Y1 - 2006/2/8

N2 - We report systematic measurements using the 59Co nuclear quadrupole resonance (NQR) technique on the cobalt oxide superconductors Na xCoO2·1.3H2O over a wide Na content range x ≤ 0.25-0.34. We find that Tc increases with decreasing x but reaches a plateau for x≤0.28. In the sample with x∼0.26, the spin-lattice relaxation rate 1/T1 shows a T3 variation below Tc and down to T∼Tc/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x,1/T1 deviates from the T3 variation below T∼2 K even though the Tc (∼4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wavevector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.

AB - We report systematic measurements using the 59Co nuclear quadrupole resonance (NQR) technique on the cobalt oxide superconductors Na xCoO2·1.3H2O over a wide Na content range x ≤ 0.25-0.34. We find that Tc increases with decreasing x but reaches a plateau for x≤0.28. In the sample with x∼0.26, the spin-lattice relaxation rate 1/T1 shows a T3 variation below Tc and down to T∼Tc/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x,1/T1 deviates from the T3 variation below T∼2 K even though the Tc (∼4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wavevector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.

UR - http://www.scopus.com/inward/record.url?scp=31144446912&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=31144446912&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/18/5/L02

DO - 10.1088/0953-8984/18/5/L02

M3 - Article

AN - SCOPUS:31144446912

VL - 18

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 5

ER -