Magnetic relaxation behavior of a spatially closed dysprosium(III) phthalocyaninato double-decker complex
Magnetic relaxation behavior of a spatially closed dysprosium(III) phthalocyaninato double-decker complex
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DOI：
10.1007/s11426-012-4615-9
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
K. Katoh;K. Umetsu;K. Breedlove Brian;M. Yamashita
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文献类型：
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作者：
K. Katoh;K. Umetsu;K. Breedlove Brian;M. Yamashita
报道了空间封闭的Dy（Ⅲ）双层Pc配合物Dy（obPc）2（1）的SMM性质，该配合物相当于一个假双核配合物.配合物1与Tb（obPc）2（3）在单斜空间群P21/P21中同晶，Tb（obPc）2（3）沿轴向沿着排列成二聚体结构。Dy-Dy金属间距离为0.756 nm，1的χ MT随T的减小而减小，表明Dy 3+离子间存在反铁磁相互作用. 1.8K时的M-H曲线显示出磁滞现象。在对1的粉末样品的交流磁化率测量中，表明1是单分子磁体（SMM），其最大值出现在22 K，交流频率（f）为1488 Hz。峰的形状急剧变化，并且当施加足以抑制磁化的量子隧穿（QTM）的Hdclarge时，峰不移位。根据阿耳忒修斯图，能垒（Δ/hc）估计为44 cm− 1，指前因子（τ0）为1.6 × 10−5s。我们的研究结果表明，SMM/磁性能的1显着变化，在直流磁场。这些弛豫机制与基态能隙和QTM有关。
The SMM properties of the spatially closed Dy(III) double-decker Pc complex Dy(obPc)2(1), which is equivalent to a pseudo dinuclear complex, are reported. Complex1crystallized with ethanol in the crystal lattice in the monoclinic space groupP21/nand was isomorphous with Tb(obPc)2(3), which is arranged in a dimer structure along thebaxis. The intermetallic Dy-Dy distance was determined to be 0.756 nm.χMTversusTplots for1decreased with a decrease inT, which suggests the existence of an antiferromagnetic (AF) interaction between the Dy3+ions. TheM-Hcurve for1at 1.8 K showed magnetic hysteresis. In ac susceptibility measurements on a powder sample of1, which were dependent on the applied ac field, indicating that1is an single molecule magnet (SMM), a maximum appeared at 22 K at an ac frequency (f) of 1488 Hz. The shape of the peaks drastically changed, and the peaks did not shift when anHdclarge enough to suppress the quantum tunneling of the magnetization (QTM) was applied. The energy barrier (Δ/hc) was estimated to be 44 cm−1with a pre-exponential factor (τ0) of 1.6 × 10−5s from an Arrhenius plot. Our results suggest that the SMM/magnetic properties of1significantly change in a dc magnetic field. These relaxation mechanisms are related to the energy gap of the ground state and to QTM.