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Title: Phase Diagram and Spin Hamiltonian of Weakly-coupled Anisotropic S=1/2 Chains in CuCl 2 .2((CD 3) 2SO)

Abstract

Field-dependent specific heat and neutron scattering measurements were used to explore the antiferromagnetic S=(1/2) chain compound CuCl{sub 2}{center_dot}2((CD{sub 3}){sub 2}SO). At zero field the system acquires magnetic long-range order below T{sub N}=0.93 K with an ordered moment of 0.44{micro}{sub B}. An external field along the b axis strengthens the zero-field magnetic order, while fields along the a and c axes lead to a collapse of the exchange stabilized order at {micro}{sub 0}H{sub c}=6 T and {micro}{sub 0}H{sub c}=4 T (extrapolated to zero temperature) and the formation of an energy gap in the excitation spectrum. We relate the field-induced gap to the presence of a staggered g-tensor and Dzyaloshinskii-Moriya interactions, which lead to effective staggered fields for magnetic fields applied along the a and c axes. Competition between anisotropy, interchain interactions, and staggered fields leads to a succession of three phases as a function of field applied along the c axis. For fields greater than {micro}{sub 0}H{sub c}, we find a magnetic structure that reflects the symmetry of the staggered fields. The critical exponent, beta, of the temperature driven phase transitions are indistinguishable from those of the three-dimensional Heisenberg magnet, while measurements for transitions driven by quantum fluctuations produce larger valuesmore » of beta.« less

Authors:
 [1];  [2];  [1];  [3];  [1];  [4]
  1. Johns Hopkins University
  2. ORNL
  3. Los Alamos National Laboratory (LANL)
  4. Brookhaven National Laboratory (BNL)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931971
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 75
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANISOTROPY; CHAINS; ENERGY GAP; EXCITATION; FLUCTUATIONS; HAMILTONIANS; MAGNETIC FIELDS; NEUTRONS; PHASE DIAGRAMS; SCATTERING; SPECIFIC HEAT; SPIN; SYMMETRY

Citation Formats

Chen, Y., Stone, Matthew B, Kenzelmann, M., Batista, C. D., Reich, D. H., and Broholm, C. L. Phase Diagram and Spin Hamiltonian of Weakly-coupled Anisotropic S=1/2 Chains in CuCl2.2((CD3)2SO). United States: N. p., 2007. Web. doi:10.1103/PhysRevB.75.214409.
Chen, Y., Stone, Matthew B, Kenzelmann, M., Batista, C. D., Reich, D. H., & Broholm, C. L. Phase Diagram and Spin Hamiltonian of Weakly-coupled Anisotropic S=1/2 Chains in CuCl2.2((CD3)2SO). United States. doi:10.1103/PhysRevB.75.214409.
Chen, Y., Stone, Matthew B, Kenzelmann, M., Batista, C. D., Reich, D. H., and Broholm, C. L. Mon . "Phase Diagram and Spin Hamiltonian of Weakly-coupled Anisotropic S=1/2 Chains in CuCl2.2((CD3)2SO)". United States. doi:10.1103/PhysRevB.75.214409.
@article{osti_931971,
title = {Phase Diagram and Spin Hamiltonian of Weakly-coupled Anisotropic S=1/2 Chains in CuCl2.2((CD3)2SO)},
author = {Chen, Y. and Stone, Matthew B and Kenzelmann, M. and Batista, C. D. and Reich, D. H. and Broholm, C. L.},
abstractNote = {Field-dependent specific heat and neutron scattering measurements were used to explore the antiferromagnetic S=(1/2) chain compound CuCl{sub 2}{center_dot}2((CD{sub 3}){sub 2}SO). At zero field the system acquires magnetic long-range order below T{sub N}=0.93 K with an ordered moment of 0.44{micro}{sub B}. An external field along the b axis strengthens the zero-field magnetic order, while fields along the a and c axes lead to a collapse of the exchange stabilized order at {micro}{sub 0}H{sub c}=6 T and {micro}{sub 0}H{sub c}=4 T (extrapolated to zero temperature) and the formation of an energy gap in the excitation spectrum. We relate the field-induced gap to the presence of a staggered g-tensor and Dzyaloshinskii-Moriya interactions, which lead to effective staggered fields for magnetic fields applied along the a and c axes. Competition between anisotropy, interchain interactions, and staggered fields leads to a succession of three phases as a function of field applied along the c axis. For fields greater than {micro}{sub 0}H{sub c}, we find a magnetic structure that reflects the symmetry of the staggered fields. The critical exponent, beta, of the temperature driven phase transitions are indistinguishable from those of the three-dimensional Heisenberg magnet, while measurements for transitions driven by quantum fluctuations produce larger values of beta.},
doi = {10.1103/PhysRevB.75.214409},
journal = {Physical Review B},
number = ,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}