A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K
A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K
复制标题
具有超过 1000 K 记录磁化反转势垒的稳定五角双锥 Dy(III) 单离子磁体
DOI：
10.1021/jacs.6b02638
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发表时间：
2016-04-27
影响因子：
15
通讯作者：
Tong, Ming-Liang
中科院分区：
文献类型：
--
作者：
Liu, Jiang;Chen, Yan-Cong;Tong, Ming-Liang
具有大自旋反转势垒的单分子磁体（SMMs）表现出缓慢的磁弛豫，从而导致磁滞回线。合成具有大能量势垒和显著慢弛豫时间的高度稳定的smm具有挑战性。在这里，我们报道了两个高度稳定和中性的Dy（III）经典配位化合物，具有五边形双锥体局部几何结构，表现出SMM行为。在未稀释的单晶中，通过微- squid测量首次观察到弱分子间相互作用。磁弛豫的研究表明，由于轴向磁各向异性增大而横向磁各向异性减弱，热激活的量子隧穿效应通过第三激发Kramers双偶态发生。结果表明，磁滞回线最大可达14k，磁弛豫的有效能垒（U-eff = 1025k）在smm中达到突破。
Single-molecule magnets (SMMs) with a large spin reversal barrier have been recognized to exhibit slow magnetic relaxation that can lead to a magnetic hysteresis loop. Synthesis of highly stable SMMs with both large energy barriers and significantly slow relaxation times is challenging. Here, we report two highly stable and neutral Dy(III) classical coordination compounds with pentagonal bipyramidal local geometry that exhibit SMM behavior. Weak intermolecular interactions in the undiluted single crystals are first observed for mononuclear lanthanide SMMs by micro-SQUID measurements. The investigation of magnetic relaxation reveals the thermally activated quantum tunneling of magnetization through the third excited Kramers doublet, owing to the increased axial magnetic anisotropy and weaker transverse magnetic anisotropy. As a result, pronounced magnetic hysteresis loops up to 14 K are observed, and the effective energy barrier (U-eff = 1025 K) for relaxation of magnetization reached a breakthrough among the SMMs.