Record Quantum Tunneling Time in an Air-Stable Exchange-Bias Dysprosium Macrocycle
Zhenhua Zhu, Sagar Paul, Chen Zhao, Jianfeng Wu, Ying Xu, Liviu Ungur, Wolfgang Wernsdorfer, Franc Meyer, Jinkui Tang
Abstract
In recent years, dysprosium macrocycle single-molecule magnets (SMMs) have received increasing attention due to their excellent air/thermal stability, strong magnetic anisotropy, and rigid molecular skeleton. However, they usually display fast zero-field quantum tunneling of the magnetization (QTM) rate, severely hindering their data storage applications. Herein, we report the design, synthesis, and characterization of an air-stable monodecker didysprosium macrocycle integrating strong single-ion anisotropy, near-perfect local crystal field (CF) symmetry, and efficient exchange bias. These indispensable features enable clear-cut elucidation of the crucial role of very weak antiferromagnetic coupling on magnetization dynamics, creating a prominent SMM with a large effective energy barrier ( U eff ) of 670 cm –1, open hysteresis loops at zero field up to 14.9 K, and a record relaxation time of QTM (τ QTM ), 24281 s, for all known nonradical-bridged lanthanide SMMs.