Magnetic properties of the $S$ = 1/2 antiferromagnetic spin-chain $\alpha-$Cu$_{2}$V$_{2}$O$_{7}$

ORAL

Abstract

Magnetic properties of the $S = 1/2$ antiferromagnetic spin-chain, $\alpha-$Cu$_{2}$V$_{2}$O$_{7}$, have been studied using magnetization and neutron scattering measurements on powder and single-crystal samples. Magnetic susceptibility reveals a Curie-Weiss temperature of $\Theta$ = -73.2(9) K with a magnetic phase transition at $T_{N}$ = 33 K while the Bonner-Fisher fit to the magnetic susceptibility for $T > T_{N}$ with magnetic field perpendicular to the crystallographic $a-$axis yields the intra-chain coupling of $\left| J\right| /k$ = 46.0(2) K. Small ferromagnetism below $T_{N}$ is due to spin-canting caused by Dzyaloshinskii-Moriya interactions. Analysis of the neutron diffraction data reveals that the Cu$^{2+}$ spins are coupled antiferromagnetically along zigzag chains, which run alternately along [011] and [01-1] directions. The ordered moment of 0.925(3) $\mu_{B}$ is predominantly along the $a-$axis. Our recent inelastic neutron scattering, which reveals atypical magnetic excitations centered at commensurate wave vectors (0, $\pm$0.25, 0) around the magnetic zone center, will also be discussed.

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Authors

  • Ganatee Gitgeatpong

    • Mahidol University, Thailand

  • Yang Zhao

    • NIST Center for Neutron Research, National Institute of Standards and Technology, USA
    • Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
    • National Institute of Standards and Technology

  • Maxim Avdeev

    • Australian Nuclear Science and Technology Organisation, Australia

  • Ross Piltz

    • Australian Nuclear Science and Technology Organisation, Australia

  • Taku Sato

    • IMRAM, Tohoku University, Japan

  • Kittiwit Matan

    • Mahidol University, Thailand