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Title: Phonon-assisted relaxation in a frustrated antiferromagnet

A thermally activated magnetic relaxation is observed using neutron spin-echo in the pyrochlore slab (kagom{acute e} bilayer) compound SrCr{sub 9x}Ga{sub 12-9x}O{sub 19} (x=0.95) in a restricted temperature range, 4K < T < 4K, above a cross-over to a low temperature relaxation regime with a weaker temperature dependence. The activation energy of the thermally activated relaxation, of the order of 7 meV, coincides with the energy of a phonon mode observed with neutron and Raman spectroscopy, indicating a phonon-assisted regime. The experimental observation of phonon-assisted process gives additional insight to the importance of spin-phonon coupling in frustrated magnets with regard to the models mostly based on purely magnetic interactions.
Authors:
 [1]
  1. ORNL
Publication Date:
OSTI Identifier:
931324
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: ICM 2006, Kyoto, Japan, 20060820, 20060820
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACTIVATION ENERGY; MAGNETS; NEUTRONS; PHONONS; PYROCHLORE; RAMAN SPECTROSCOPY; RELAXATION; SPIN ECHO; TEMPERATURE DEPENDENCE