Exchange-coupling constants, spin density map, and Q dependence of the inelastic neutron scattering intensity in single-molecule magnets
Exchange-coupling constants, spin density map, and Q dependence of the inelastic neutron scattering intensity in single-molecule magnets
复制标题
单分子磁体中非弹性中子散射强度的交换耦合常数、自旋密度图和 Q 依赖性
DOI：
10.1103/physrevb.75.174438
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发表时间：
2007
影响因子：
3.7
通讯作者：
H. Mutka
中科院分区：
文献类型：
--
作者：
O. Waldmann;R. Bircher;G. Carver;A. Sieber;H. Gudel;H. Mutka
研究了单分子磁体基态自旋多重态跃迁的非弹性中子散射强度与Q的关系。对于这些转变，Q依赖性与基态的自旋密度图有关，而基态的自旋密度图又受团簇中的海森堡交换相互作用的影响。这提供了从自旋基态内的INS跃迁的Q依赖性推断交换耦合常数的可能性。以Mn_（12）分子S = 10多重峰中的M = +-10 -> +-9跃迁为例，探讨了这种策略的潜力.计算粉末以及单晶Mn 12样品的各种交换耦合的情况下，在文献中讨论的Q依赖性。将结果与Mn 12的粉末样品上的文献数据和Mn 12的约500个单晶的定向阵列上的测量进行比较。计算出的Q依赖表现出显着的变化与交换耦合常数，特别是对于单晶样品，但实验结果并不允许明确的测定。然而，尽管具有挑战性，但合适的实验是在当今仪器的范围内的。
The Q dependence of the inelastic neutron scattering (INS) intensity of transitions within the ground-state spin multiplet of single-molecule magnets (SMMs) is considered. For these transitions, the Q dependence is related to the spin density map in the ground state, which in turn is governed by the Heisenberg exchange interactions in the cluster. This provides the possibility to infer the exchange-coupling constants from the Q dependence of the INS transitions within the spin ground state. The potential of this strategy is explored for the M = +-10 -> +- 9 transition within the S = 10 multiplet of the molecule Mn12 as an example. The Q dependence is calculated for powder as well as single-crystal Mn12 samples for various exchange-coupling situations discussed in the literature. The results are compared to literature data on a powder sample of Mn12 and to measurements on an oriented array of about 500 single-crystals of Mn12. The calculated Q dependence exhibits significant variation with the exchange-coupling constants, in particular for a single-crystal sample, but the experimental findings did not permit an unambiguous determination. However, although challenging, suitable experiments are within the reach of today's instruments.