Magnetic Properties of the quasi-2D S=1/2 Heisenberg antiferromagnet [Cu(pyz)$_2$(HF$_2$)]PF$_6$

ORAL

Abstract

We report on electron spin resonance, high-field magnetization, and specific-heat studies of [Cu(pyz)$_2$(HF$_2$)]PF$_6$ single crystals, identified as a quasi-two-dimensional spin-1/2 Heisenberg antiferromagnet. Our measurements revealed $J_{inter}/J_{intra}\leq $ 0.063 and $A/J\sim$ 0.003, where $J_{inter}$, $J_{intra}$, $J$ are the interplane, intraplane and mean exchange interactions, respectively, and $A$ is the anisotropy constant. It is argued that the magnetic properties of this material (including high-magnetic-field magnetization and the temperature-field phase diagram) are strongly affected by two-dimensional spin fluctuations, despite of onset of 3D long-range magnetic ordering at $T_N\approx 4.4$~K. The ESR magnetic excitation spectrum in the 3D ordered phase is studied in detail.

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Authors

  • S. Zvyagin

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany
    • Dresden High Magnetic Field Laboratory/FZD
    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden - Rossendorf

  • E. \v{C}i\v{z}m\'{a}r

    • Centre of Low Temperature Physics, P.J. \v{S}afarik University, Ko\v{s}ice, Slovakia

  • R. Beyer

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany

  • M. Uhlarz

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany

  • M. Ozerov

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany

  • Y. Skourski

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany

  • J. Wosnitza

    • Dresden High Magnetic Field Laboratory (HLD), FZ Dresden-Rossendorf, Dresden, Germany

  • J.L. Manson

    • Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA

  • J.A. Schlueter

    • Materials Science Division, Argonne National Laboratory, Argonne, IL , USA