Thermal transport and magnetotransport properties of CuCr 1-xMgxO2 with a spin-3/2 antiferromagnetic triangular lattice

Tetsuji Okuda, Satoshi Oozono, Takumi Kihara, Masashi Tokunaga

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

We have investigated the thermal conductivity (k) and magnetoresistance (MR) of non-doped and hole-doped delafossite CuCrO2 with a spin-3/2 antiferromagnetic (AF) triangular sublattice. The phonon mean free path above the Néel temperature (TN) deduced from k and lattice specific heat is almost identical to the magnetic correlation length, which indicates that, for both compounds, spin fluctuation enhanced in a geometrically frustrated lattice is strongly coupled with acoustic phonon above TN. k below TN is significantly suppressed by Mg substitution, suggesting the introduction of some disorder into the 120° Néel state. For the hole-doped CuCr0.97Mg0.03O2, a negative MR is observed above TN, which is enhanced with a decrease in T toward TN, while a component of positive MR appears below T N and the residual negative MR component is observed in a high magnetic field, indicating that spin fluctuation coupled with electrical conductivity is critically enhanced above TN and remains below T N. These results evidence that the 120° Néel state is partially disordered by a doped itinerant hole coupled with spin fluctuation, although AF transition is certainly promoted. The dynamic partial disorder may stabilize the Néel order through an order-bydisorder mechanism.

Original languageEnglish
Article number014706
JournalJournal of the Physical Society of Japan
Volume82
Issue number1
DOIs
Publication statusPublished - 2013 Jan 1
Externally publishedYes

Keywords

  • Antiferromagnetic triangular lattice
  • Frustration
  • Magnetoresistance
  • Thermal conductivity

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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