Evolution of Magnetism in Single-Crystal Ca2Ru1-xIrxO4 (0 $\le $ x $\le $ 0.65)

ORAL

Abstract

We report structural, magnetic, transport and thermal properties of single-crystal Ca$_{2}$Ru$_{\mathrm{1-x}}$Ir$_{x}$O$_{4}$ (0 $\le $ x $\le $ 0.65). Ca$_{2}$RuO$_{4}$ is a structurally-driven Mott insulator with a metal-insulator transition at $T_{\mathrm{MI}} =$ 357 K, followed by a well-separated antiferromagnetic order at $T_{\mathrm{N}} =$ 110 K. Substituting Ru with Ir enhances the spin-orbit coupling (SOC) and causes further orthorhombic distortions. As a result, a pronounced weak ferromagnetic behavior occurs, which enhances dramatically with increasing Ir concentration. The magnetic ordering temperature $T_{\mathrm{N}}$ increases from 110 K at $x =$ 0 to 215 K at x $=$ 0.65, along with enhanced magnetic anisotropy due to SOC. In addition, with increasing x, the metal-insulator transition $T_{\mathrm{MI}}$ increases initially and vanishes eventually.

*This work was supported by the National Science Foundation (NSF) under Grants No. DMR-0856234, and No. DMR-1265162.

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Authors

  • S.J. Yuan

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA
    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • J. Terzic

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • J.C. Wang

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • L. Li

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • T.F. Qi

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • W.H. Song

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • S. Aswartham

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • G. Cao

    • Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA