A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K

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• 作者：Jiang Liu ; Yan-Cong Chen ; Jun-Liang Liu ; Veacheslav Vieru ; Liviu Ungur ; Jian-Hua Jia ; Liviu F. Chibotaru ; Yanhua Lan ; Wolfgang Wernsdorfer ; Song Gao ; Xiao-Ming Chen ; Ming-Liang Tong
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：April 27, 2016
• 年：2016
• 卷：138
• 期：16
• 页码：5441-5450
• 全文大小：741K
• 年卷期：0
• ISSN：1520-5126

文摘

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.