Spin dynamics of an isotropic singlet-ground-state antiferromagnet with alternating strong and weak interactions: An inelastic-neutron-scattering study of the dimer compound Cs 3 Cr 2 Br 9
Spin dynamics of an isotropic singlet-ground-state antiferromagnet with alternating strong and weak interactions: An inelastic-neutron-scattering study of the dimer compound Cs 3 Cr 2 Br 9
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具有交替强弱相互作用的各向同性单线态反铁磁体的自旋动力学：二聚体化合物 Cs 3 Cr 2 Br 9 的非弹性中子散射研究
DOI：
10.1103/physrevb.30.6300
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发表时间：
1984
影响因子：
3.7
通讯作者：
J. Kjems
中科院分区：
文献类型：
--
作者：
B. Leuenberger;A. Stebler;H. Güdel;A. Furrer;R. Feile;J. Kjems
用非弹性中子散射研究了二聚体化合物Cs3Cr2Br9的粉末和单晶样品。在1.6 K时，单重态到三重态的二聚体激发表现出明显的能量色散，作为弱的二聚体间相互作用的结果。结果解释内的随机相位近似与海森堡哈密顿量的使用，并考虑最近邻相互作用。理论和实验之间的一致性是极好的。在1.6 K下得到了三个交换参数：J=− 1.03 meV（二聚体内），J p=− 0.054 meV（二聚体间，亚晶格内）和J c=− 0.039 meV（二聚体间，亚晶格间）。激励表现出软模式行为。然而，在1.6K以上不会发生排序。
Powder and single-crystal samples of the dimer compound Cs 3 Cr 2 Br 9 have been studied by inelastic neutron scattering. At 1.6 K, the singlet-to-triplet dimer excitation exhibits pronounced energy dispersion as a result of weak interdimer interactions. The results are interpreted within the random-phase approximation with use of a Heisenberg Hamiltonian and considering only nearest-neighbor interactions. The agreement between theory and experiment is excellent. Three exchange parameters have been obtained at 1.6 K: J=− 1.03 meV (intradimer), J p=− 0.054 meV (interdimer, intrasublattice), and J c=− 0.039 meV (interdimer, intersublattice). The excitation shows soft-mode behavior. However, an ordering does not occur above 1.6 K.