Magnetic properties of the S=1/2 quasi square lattice antiferromagnet CuF2(H2O)2(pyz) (pyz=pyrazine) investigated by neutron scattering

Abstract

We have performed elastic and inelastic neutron experiments on single crystal samples of the coordination polymer compound CuF2(H2O)2(pyz) (pyz=pyrazine) to study the magnetic structure and excitations. The elastic neutron diffraction measurements indicate a collinear antiferromagnetic structure with moments oriented along the [0.7 0 1] real-space direction and an ordered moment of 0.60 +/- 0.03 muB/Cu. This value is significantly smaller than the single ion magnetic moment, reflecting the presence of strong quantum fluctuations. The spin wave dispersion from magnetic zone center to the zone boundary points (0.5 1.5 0) and (0.5 0 1.5) can be described by a two dimensional Heisenberg model with a nearest neighbor magnetic exchange constant J2d = 0.934 +/-0.0025 meV. The inter-layer interaction Jperp in this compound is less than 1.5% of J2d. The spin excitation energy at the (0.5 0.5 0.5) zone boundary point is reduced when compared to the (0.5 1 0.5) zone boundary point by ~10.3 +/- 1.4 %. This zone boundary dispersion is consistent with quantum Monte Carlo and series expansion calculations which include corrections for quantum fluctuations to linear spin wave theory.

arXiv comment7 pages, 6 figures

References in corpus (10)

• Spin waves and electronic interactions in La2CuO4
• The new Cold Neutron Chopper Spectrometer at the Spallation Neutron Source - Design and Performance
• Modeling the Unconventional Superconducting Properties of Expanded A${}_3$C${}_{60}$ Fullerides
• High-energy magnon dispersion and multi-magnon continuum in the two-dimensional Heisenberg antiferromagnet
• Further Series Studies of the Spin-1/2 Heisenberg Antiferromagnet at T=0: Magnon Dispersion and Structure Factors
• Spin-wave excitation spectra and spectral weights in square lattice antiferromagnets
• The Two-Dimensional Square-Lattice S=1/2 Antiferromagnet Cu(pz)${}_2$(ClO${}_4$)${}_2$
• Quantum effects in a weakly-frustrated S=1/2 two-dimensional Heisenberg antiferromagnet in an applied magnetic field
• Isotope effect in quasi-two-dimensional metal-organic antiferromagnets
• Magnetic Excitation Spectrum of the Square Lattice S=1/2 Heisenberg Antiferromagnet K2V3O8

Cited by in corpus (6)

• The Cold Neutron Chopper Spectrometer at the Spallation Neutron Source - A Review of the first 8 Years of Operation
• Evolution of magnetic interactions in a pressure-induced Jahn-Teller driven magnetic dimensionality switch
• High-energy spin waves in the spin-1 square-lattice antiferromagnet La${}_2$NiO${}_4$
• The magnetic ground state of two isostructual polymeric quantum magnets, [Cu(HF${}_2$)(pyrazine)${}_2$]SbF${}_6$ and [Co(HF${}_2$)(pyrazine)${}_2$]SbF${}_6$, investigated with neutron powder diffraction
• Dimensional reduction by pressure in the magnetic framework material CuF${}_2$(D${}_2$O)${}_2$pyz: from spin-wave to spinon excitations
• Magnetic excitations from the two-dimensional interpenetrating Cu framework in Ba${}_2$Cu${}_3$O${}_4$Cl${}_2$