Magnetic properties of triangular lattice Ca$_4$IrO$_6$ and Ca$_{2.5}$Sr$_{1.5}$IrO$_6$

ORAL

Abstract

We report a structural, thermodynamic, and transport study of single-crystal Ca$_4$IrO$_6$ and Ca$_{2.5}$Sr$_{1.5}$IrO$_6$. The isostructural Ca$_4$IrO$_6$ and Ca$_{2.5}$Sr$_{1.5}$IrO$_6$ feature a triangular lattice of spin chains running along the \emph{c} axis. The underlying properties of the two systems are characterized by a partial antiferromagnetic order occuring at 12 K and 9 K for Ca$_4$IrO$_6$ and Ca$_{2.5}$Sr$_{1.5}$IrO$_6$, respectively, a small entropy removal associated with the phase transition, and a sizable low-temperature specific heat linearly proportional to temperature. The detailed results will be discussed along with comparisons drawn with other related systems such as Ca$_5$Ir$_3$O$_{12}$.

*This work was supported by NSF through grants DMR-0856234 and EPS-0814194.

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Authors

  • K.H. Butrouna

    • Center for Advanced Materials, University of Kentucky

  • L. Li

    • Center for Advanced Materials, University of Kentucky
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky

  • T.F. Qi

    • Center for Advanced Materials, University of Kentucky
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky

  • O.B. Korneta

    • Center for Advanced Materials, University of Kentucky
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky
    • Department of Physics and Astronomy and Center for Advanced Materials, University of Kentucky

  • J. Terzic

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky
    • Center for Advanced Materials, University of Kentucky

  • E. Akbari

    • Center for Advanced Materials, University of Kentucky

  • S. Parkin

    • Center for Advanced Materials, University of Kentucky
    • Center for Advanced Materials, Department of Chemistry, University of Kentucky

  • S.J. Yuan

    • Department of Physics, Shanghai University

  • Gang Cao

    • Center for Advanced Materials, University of Kentucky
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky
    • Center for Advanced Materials and Department of Physics and Astronomy, University of Kentucky