Spin dynamics of molecular nanomagnets unravelled at atomic scale by four-dimensional inelastic neutron scattering
Spin dynamics of molecular nanomagnets unravelled at atomic scale by four-dimensional inelastic neutron scattering
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DOI：
10.1038/nphys2431
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发表时间：
2012-12-01
期刊：
影响因子：
19.6
通讯作者：
Santini, Paolo
中科院分区：
文献类型：
--
作者：
Baker, Michael L.;Guidi, Tatiana;Santini, Paolo
分子纳米磁体是有限尺寸自旋系统的首批示例之一，并且已成为解决量子动力学中多种现象的试验台。事实上，对于足够短的时间尺度，自旋波函数根据适当的自旋哈密顿量一致演化，可以对其进行设计以满足特定要求。不幸的是，到目前为止还不可能直接确定这些自旋动力学。在这里，我们展示了最近开发的仪器在大部分倒易空间中产生四维非弹性中子散射函数，并使自旋动力学能够直接确定。我们使用 Cr-8 反铁磁环作为基准来展示这种方法的潜力，例如，它使我们能够检查量子涨落如何沿着环传播或测试尼尔矢量隧道框架的有效性程度。
Molecular nanomagnets are among the first examples of finite-size spin systems and have been test beds for addressing several phenomena in quantum dynamics. In fact, for short-enough timescales the spin wavefunctions evolve coherently according to an appropriate spin Hamiltonian, which can be engineered to meet specific requirements. Unfortunately, so far it has been impossible to determine these spin dynamics directly. Here we show that recently developed instrumentation yields the four-dimensional inelastic-neutron scattering function in vast portions of reciprocal space and enables the spin dynamics to be determined directly. We use the Cr-8 antiferromagnetic ring as a benchmark to demonstrate the potential of this approach which allows us, for example, to examine how quantum fluctuations propagate along the ring or to test the degree of validity of the Neel-vector-tunnelling framework.