A near-ideal molecule-based Haldane spin chain

ORAL

Abstract

We report on a new molecule-based magnet NiI2(3,5-lutidine)4 characterized using x-ray diffraction, electron-spin resonance, magnetometry, inelastic neutron scattering and muon-spin relaxation. The system is a near-ideal realization of the S = 1 Haldane chain with intrachain exchange J = 17.5 K, energy gaps of 5.3 K and 7.7 K split by easy-axis anisotropy D=−1.2 K, and with no sign of magnetic order down to 20 mK. The value D/J=−0.07 implies one of the most isotropic Haldane systems yet discovered, while the ratio Δ/J = 0.40(1) (where Δ is the average gap size) is close to the ideal theoretical value, suggesting a very high degree of magnetic isolation of the chains. The Haldane gap is closed by orientation-dependent critical fields 5.3 T and 4.3 T, which are readily accessible experimentally. The fully polarized state occurs above 46.0 T. The results are explicable within the so-called fermion model, which is in contrast to other reported easy-axis Haldane systems. The flexible nature of this molecule-based material readily permits tuning via applied pressure and introduction of disorder along the exchange pathway.

*This project has received funding from the European Research Council (grant no. 681260). We also thank the NHMFL, EPSRC, STFC, NSF, DoE and the State of Florida.

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Presenters

  • Paul Goddard

    • Physics, Warwick University
    • Department of Physics, University of Warwick
    • Univ of Warwick
    • Physics, University of Warwick
    • University of Warwick

Authors

  • Paul Goddard

    • Physics, Warwick University
    • Department of Physics, University of Warwick
    • Univ of Warwick
    • Physics, University of Warwick
    • University of Warwick

  • Robert C Williams

    • Department of Physics, University of Warwick
    • Univ of Warwick

  • William J. Blackmore

    • Univ of Warwick

  • Sam Curley

    • Department of Physics, University of Warwick
    • Univ of Warwick
    • Physics, University of Warwick

  • Martin Lees

    • Univ of Warwick
    • University of Warwick
    • Department of Physics, University of Warwick
    • Physics Department, University of Warwick, Coventry, CV4 7AL, United Kingdom

  • Serena M Birnbaum

    • Los Alamos National Laboratory

  • John Singleton

    • National High Magnetic Field Lab, Los Alamos
    • Los Alamos National Laboratory
    • NHMFL, Los Alamos National Laboratory
    • National High Magnetic Field Laboratory, Los Alamos National Laboratory
    • NHMFL, Los Alamos National Lab
    • Los Alamos National Lab.

  • Benjamin Huddart

    • Durham University
    • Physics, Durham University

  • Thomas Hicken

    • Durham University
    • Centre for Materials Physics, Durham University
    • Physics, Durham University

  • Tom Lancaster

    • Durham University
    • Centre for Materials Physics, Durham University
    • Physics, University of Durham
    • Physics, Durham University

  • Stephen Blundell

    • Department of Physics, University of Oxford
    • Department of Physics, University of Oxford, Oxford, UK
    • University of Oxford
    • Physics, University of Oxford

  • Fan Xiao

    • Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute
    • Paul Scherrer Institut

  • Andrew Ozarowski

    • Florida State University

  • Francis L. Pratt

    • STFC
    • ISIS Neutron and Muon Source

  • David J Voneshen

    • ISIS Neutron and Muon Source

  • Zurab Guguchia

    • Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute
    • Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Switzerland
    • Paul Scherrer Institut
    • Paul-Scherrer-Institut, Villigen, Switzerland
    • Paul Scherrer Institute

  • Christopher Baines

    • Paul Scherrer Institut
    • Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut

  • J.A. Schlueter

    • Argonne National Laboratory

  • Danielle Y. Villa

    • Eastern Washington University

  • Jamie Manson

    • Department of Chemistry and Biochemistry, Eastern Washington University
    • Eastern Washington University