Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark.
Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Nat Commun. 2018 Mar 29;9(1):1292. doi: 10.1038/s41467-018-03706-x.
Total control over the electronic spin relaxation in molecular nanomagnets is the ultimate goal in the design of new molecules with evermore realizable applications in spin-based devices. For single-ion lanthanide systems, with strong spin-orbit coupling, the potential applications are linked to the energetic structure of the crystal field levels and quantum tunneling within the ground state. Structural engineering of the timescale of these tunneling events via appropriate design of crystal fields represents a fundamental challenge for the synthetic chemist, since tunnel splittings are expected to be suppressed by crystal field environments with sufficiently high-order symmetry. Here, we report the long missing study of the effect of a non-linear (C) to pseudo-linear (D) change in crystal field symmetry in an otherwise chemically unaltered dysprosium complex. From a purely experimental study of crystal field levels and electronic spin dynamics at milliKelvin temperatures, we demonstrate the ensuing threefold reduction of the tunnel splitting.
对分子磁体中电子自旋弛豫的完全控制是设计具有越来越多实际应用的自旋基器件的新分子的最终目标。对于具有强自旋轨道耦合的单离子镧系系统，潜在的应用与晶体场能级的能量结构和基态中的量子隧穿有关。通过适当的晶体场设计对这些隧穿事件的时间尺度进行结构工程设计，这对于合成化学家来说是一个基本的挑战，因为预计隧道分裂会受到具有足够高阶对称性的晶体场环境的抑制。在这里，我们报告了一个镝配合物中晶体场对称性从非线性 (C) 到准线性 (D) 变化的长期缺失的研究。通过在毫开尔文温度下对晶体场能级和电子自旋动力学的纯实验研究，我们证明了隧道分裂随之减少了三倍。
