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Title: Coupled antiferromagnetic spin- 12 chains in green dioptase Cu6[Si6O18]·6H2O

In this paper, we report inelastic neutron scattering measurements of the magnetic excitations of green dioptase Cu6[Si6O18]∙6H2O. The observed spectrum contains two magnetic modes and a prominent spin gap that is consistent with the ordered ground state of Cu moments coupled antiferromagnetically in spiral chains along the c axis and ferromagnetically in ab planes on the hexagonal cell. The data are in excellent agreement with a spin- 12Hamiltonian that includes antiferromagnetic nearest-neighbor intrachain coupling Jc=10.6(1) meV, ferromagnetic interchain coupling Jab=₋1.2 (1) meV, and exchange anisotropy ΔJc=0.14(1) meV. We calculated the sublattice magnetization to be strongly reduced, ~0.39μB. This appears compatible with a reduced Néel temperature, TN=14.5K<c, and can be explained by a presence of quantum spin fluctuations
Authors:
 [1] ; ;  [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Publication Date:
OSTI Identifier:
1239762
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 6; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR), Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS