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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.

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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