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Title: Magnetic properties of the S=1/2 square lattice antiferromagnet CuF2(H2O)2(pyz)

Abstract

We have performed elastic and inelastic neutron scattering experiments on single crystal samples of the coordination polymer compound CuF{sub 2}(H{sub 2}O){sub 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 {micro}B/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 J{sub 2D} = 0.934 {+-} 0.0025 meV. The interlayer interaction J{sub perp} in this compound is less than 1.5% of J{sub 2D}. 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 {approx}10.3% {+-} 1.4%. This zone boundary dispersion is consistent with quantum Monte Carlo and series expansion calculations for the S=1/2 Heisenberg square lattice antiferromagnet, which include corrections for quantum fluctuations to linear spin wave theory.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [3];  [1]
  1. ORNL
  2. Argonne National Laboratory (ANL)
  3. Eastern Washington University
Publication Date:
Research Org.:
High Flux Isotope Reactor; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1050363
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 86; Journal Issue: 6; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; EXCITATION; FLUCTUATIONS; HEISENBERG MODEL; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; MONOCRYSTALS; NEUTRON DIFFRACTION; NEUTRONS; POLYMERS; SCATTERING; SERIES EXPANSION; SPIN; SPIN WAVES

Citation Formats

Wang, Cuihuan, Lumsden, Mark D, Fishman, Randy Scott, Ehlers, Georg, Hong, Tao, Tian, Wei, Cao, Huibo, Podlesnyak, Andrey A, Dunmars, C, Schlueter, J. A., Manson, J. L., and Christianson, Andrew D. Magnetic properties of the S=1/2 square lattice antiferromagnet CuF2(H2O)2(pyz). United States: N. p., 2012. Web. doi:10.1103/PhysRevB.86.064439.
Wang, Cuihuan, Lumsden, Mark D, Fishman, Randy Scott, Ehlers, Georg, Hong, Tao, Tian, Wei, Cao, Huibo, Podlesnyak, Andrey A, Dunmars, C, Schlueter, J. A., Manson, J. L., & Christianson, Andrew D. Magnetic properties of the S=1/2 square lattice antiferromagnet CuF2(H2O)2(pyz). United States. doi:10.1103/PhysRevB.86.064439.
Wang, Cuihuan, Lumsden, Mark D, Fishman, Randy Scott, Ehlers, Georg, Hong, Tao, Tian, Wei, Cao, Huibo, Podlesnyak, Andrey A, Dunmars, C, Schlueter, J. A., Manson, J. L., and Christianson, Andrew D. Sun . "Magnetic properties of the S=1/2 square lattice antiferromagnet CuF2(H2O)2(pyz)". United States. doi:10.1103/PhysRevB.86.064439.
@article{osti_1050363,
title = {Magnetic properties of the S=1/2 square lattice antiferromagnet CuF2(H2O)2(pyz)},
author = {Wang, Cuihuan and Lumsden, Mark D and Fishman, Randy Scott and Ehlers, Georg and Hong, Tao and Tian, Wei and Cao, Huibo and Podlesnyak, Andrey A and Dunmars, C and Schlueter, J. A. and Manson, J. L. and Christianson, Andrew D},
abstractNote = {We have performed elastic and inelastic neutron scattering experiments on single crystal samples of the coordination polymer compound CuF{sub 2}(H{sub 2}O){sub 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 {micro}B/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 J{sub 2D} = 0.934 {+-} 0.0025 meV. The interlayer interaction J{sub perp} in this compound is less than 1.5% of J{sub 2D}. 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 {approx}10.3% {+-} 1.4%. This zone boundary dispersion is consistent with quantum Monte Carlo and series expansion calculations for the S=1/2 Heisenberg square lattice antiferromagnet, which include corrections for quantum fluctuations to linear spin wave theory.},
doi = {10.1103/PhysRevB.86.064439},
journal = {Physical Review B},
issn = {1098-0121},
number = 6,
volume = 86,
place = {United States},
year = {2012},
month = {1}
}