Zhang Xuejing, Liu Shuang, Vieru Veacheslav, Xu Na, Gao Chen, Wang Bing-Wu, Shi Wei, Chibotaru Liviu F, Gao Song, Cheng Peng, Powell Annie K
College of Chemistry, Key Laboratory of, Advanced Energy Materials Chemistry (MOE), Nankai University, Tianjin, 300071, P.R. China.
State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, P.R. China.
Chemistry. 2018 Apr 20;24(23):6079-6086. doi: 10.1002/chem.201705350. Epub 2018 Mar 6.
Increasing both the energy barrier for magnetization reversal and the coercive field of the hysteresis loop are significant challenges in the field of single-molecule magnets (SMMs). Coordination geometries of lanthanide ions and magnetic interactions between lanthanide ions are both important for guiding the magnetic behavior of SMMs. We report a high energy barrier of 657 K (457 cm ) in a diamagnetic-ion-diluted lanthanide chain compound with a constrained bisphenoid symmetry (D ); this energy barrier is substantially higher than the barrier of 567 K (394 cm ) of the non-diluted chain compound with intrachain ferromagnetic interactions. Although intrachain magnetic interaction lowers the energy barrier for magnetization reversal, it can greatly enhance the coercive fields and zero-field remanence of the hysteresis loops, which is crucial for the rational design of high-performance SMMs. Factors related to the coordination sphere of the lanthanide center, which govern the high magnetic relaxation barriers through the second excited Kramer's doublets and the magnetic interactions that affect the hysteresis loops, were revealed through ab initio calculations.
提高磁化反转的能垒以及磁滞回线的矫顽场是单分子磁体(SMMs)领域的重大挑战。镧系离子的配位几何结构以及镧系离子之间的磁相互作用对于指导SMMs的磁行为都很重要。我们报道了一种具有受限双酚对称性(D)的抗磁离子稀释镧系链状化合物中高达657 K(457 cm)的高能垒;该能垒显著高于具有链内铁磁相互作用的未稀释链状化合物的567 K(394 cm)能垒。尽管链内磁相互作用降低了磁化反转的能垒,但它可以极大地增强磁滞回线的矫顽场和零场剩磁,这对于高性能SMMs的合理设计至关重要。通过从头算计算揭示了与镧系中心配位球相关的因素,这些因素通过第二激发克莱默双重态控制高磁弛豫能垒以及影响磁滞回线的磁相互作用。