The spin state transition in LaCoO$_{3}$; revising a revision

ORAL

Abstract

Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-$L_{2,3}$ edge we demonstrate that the spin state transition in LaCoO$_{3}$ can be well described by a low-spin ground state and a high-spin first excited state which becomes populated at elevated temperatures. From the temperature dependence of the spectral lineshapes we find that LaCoO$_{3}$ at finite temperatures is an inhomogeneous mixed-spin-state system. Crucial is that the magnetic circular dichroism signal in the paramagnetic state carries a large orbital momentum. This directly shows that the currently accepted low-/intermediate-spin picture is at variance, and that instead the original low-/high-spin scenario is the better \textit{ansatz}.

–

Authors

  • L. H. Tjeng

  • M. W. Haverkort

  • Z. Hu

  • T. Burnus

  • C. Zobel

  • M. Reuther

  • H. Hartmann

  • T. Lorenz

    • II. Physikalisches Institut, Universit\"{a}t zu K\"{o}ln, Germany

  • J. C. Cezar

  • N. B. Brookes

    • European Synchrotron Radiation Facility, Grenoble, France

  • A. Tanaka

    • Department of Quantum Matter, ADSM, Hiroshima University, Japan

  • H. H. Hsieh

    • Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan

  • H.-J. Lin

  • C. T. Chen

    • National Synchrotron Radiation Research Center, Hsinchu, Taiwan