A resonant ultrasound spectroscopy study of the phase transitions in Na$_{0.75}$CoO$_{2}$

ORAL

Abstract

The layered transition metal oxides Na$_{x}$CoO$_{2}$ have attracted much interest in the past few years. Crystals with the $x\simeq0.75$ composition undergo an order-disorder transition near 340 K, a spin-density-wave transition near 22 K and other subtle transitions at intermediate temperatures. These phase transitions, likely related to a rearrangement of the Na atoms among the available sites, have been mapped out using resonant ultrasound spectroscopy. The results are modeled within the Landau theory for second order phase transitions. [Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725]

–

Authors

  • Veerle Keppens

  • Rapha\"el P. Hermann

  • Zhiying Zhang

  • Kathleen Affholter

    • Materials Science and Engineering, The University of Tennessee, USA

  • Ivan Sergienko

    • Department of Physics, The University of Tennessee, USA, and Condensed Matter Sciences Division, Oak Ridge National Laboratory, USA

  • Rongying Jin

  • Brian C. Sales

  • David G. Mandrus

    • Condensed Matter Sciences Division, Oak Ridge National Laboratory, USA