Zhang Qing, Baker Michael L, Li Shiqi, Sarachik Myriam P, Baldoví José J, Gaita-Ariño Alejandro, Coronado Eugenio, Alexandropoulos Dimitris I, Stamatatos Theocharis C
Department of Physics, Graduate Center, CUNY, New York, New York 10016, USA.
Nanoscale. 2019 Aug 15;11(32):15131-15138. doi: 10.1039/c9nr05182a.
The enhancement of toroic motifs through coupling toroidal moments within molecular nanomagnets is a new, interesting and relevant approach for both fundamental research and potential quantum computation applications. We investigate a Dy8 molecular cluster and discover it has a antiferrotoroic ground state with slow magnetic relaxation. The experimental characterization of the magnetic anisotropy axes of each magnetic center and their exchange interactions represents a considerable challenge due to the non-magnetic nature of the toroidal motif. To overcome this and obtain access to the low energy states of Dy8 we establish a multi-orientation single-crystal micro Hall sensor magnetometry approach. Using an effective Hamiltonian model we then unpick the microscopic spin structure of Dy8, leading to a canted antiferrotoroidic tetramer molecular ground state. These findings are supported with electrostatic calculations that independently confirm the experimentally determined magnetic anisotropy axes for each DyIII ion within the molecule.
通过在分子纳米磁体中耦合环形矩来增强环形 motif 是一种对基础研究和潜在量子计算应用都新颖、有趣且相关的方法。我们研究了一个 Dy8 分子簇，发现它具有反铁环形基态且磁弛豫缓慢。由于环形 motif 的非磁性本质，对每个磁中心的磁各向异性轴及其交换相互作用进行实验表征是一项相当大的挑战。为了克服这一问题并获得 Dy8 的低能态，我们建立了一种多取向单晶微霍尔传感器磁强计方法。然后，使用有效哈密顿量模型，我们解开了 Dy8 的微观自旋结构，得出了一个倾斜的反铁环形四聚体分子基态。这些发现得到了静电计算的支持，该计算独立地证实了分子内每个 DyIII 离子的实验确定的磁各向异性轴。
