Magnetic excitations and exchange interactions in the spin-1/2 two-leg ladder compound La6Ca8Cu24O41
Magnetic excitations and exchange interactions in the spin-1/2 two-leg ladder compound La6Ca8Cu24O41
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DOI：
10.1103/physrevb.62.8903
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发表时间：
2000-10-01
影响因子：
3.7
通讯作者：
Mikeska, HJ
中科院分区：
文献类型：
--
作者：
Matsuda, M;Katsumata, K;Mikeska, HJ
利用脉冲中子源，我们已经能够观察到来自La6Ca8Cu24O41梯子的高能非弹性信号。这些信号构成了最低三重态激发的磁振子分支(类似于30小于或等于E小于或等于类似于190 meV)。仅对包括腿(J(腿))和横档(J(横档))的耦合的理论进行拟合，得到的值J(腿)/J(横档)类似于2，这与几何考虑和精确对角化计算的预期不一致。当我们的数据被拟合为J(腿)=J(横档)=110 meV和四自旋交换相互作用J(环)=16.5 meV时，这种不一致性被消除。
Using a pulsed neutron source we have been able to observe inelastic signals at high energies from the ladders of La6Ca8Cu24O41. These signals constitute the magnon branch (similar to 30 less than or equal to E less than or equal to similar to 190 meV) for the lowest triplet excitation. A fit to a theory including a coupling along the leg (J(leg)) and rung (J(rung)) alone gives the value J(leg)/J(rung) similar to 2 that is not consistent with expectations from a geometrical consideration and the exact diagonalization calculation. This inconsistency is removed when our data are fitted with J(leg) = J(rung) = 110 meV and a four-spin exchange interaction, J(ring) = 16.5 meV.