摘要
我们合成了一个双核Dy配合物[Dy_2(DMOP)_2(DBM)_4(CHCl_3)_4](1)(DMOP=2,6-二甲氧基苯酚)并对其进行了单分子磁性研究~([1])。从零场交流磁化率虚部对温度的作图看到明显的温度依赖现象,表明其具有显著的慢磁弛豫行为,能垒为98 K。进一步利用磁稀释实验阐明了磁弛豫的单分子来源和镝离子间磁耦合对整个分子磁各向异性的关键作用~([2]),稀释后的样品观察到了蝴蝶状的磁滞回线。由此说明在配合物中分子内邻近Dy(Ⅲ)离子间磁耦合与占主导的单离子磁各向异性共同抑制了量子隧穿使分子表现出显著的慢弛豫行为。
A dinuclear Dy2 complex[Dy_2(DMOP)_2(DBM)_4(CHCl_3)_4](1)(DMOP = 2,6-dimethoxyphenol) bridged by DMOP was structurally and magnetically characterized.The out-of-phase(χ″) component of the ac susceptibility clearly exhibits a temperature dependent full peak with maximum,which displays remarkable slow magnetic relaxation behavior under zero dc field with an anisotropic barrier of U_(eff)/k_B = 98 K.The magnetic dilution method was employed in order to elucidate that the slow magnetic relaxation is purely of molecular origin and the effective role of the intramolecular coupling on the molecular magnetic anisotropy.A butterfly-shaped hysteresis loop was observed in the diluted samples.Consequently,the dominant single-ion anisotropy was found to be entangled with Dy-Dy coupling to suppress the quantum tunneling of the magnetization and generate the significant slow relaxation behavior.
引文
[1]Long,J.;Habib,F.;Lin,P.-H.;Korobkov,I.;Enright,G.;Ungur,L.;Wernsdorfer,W.;Chibotaru,L.F.;Murugesu,M.J.Am.Chem.Soc.2011,133:5319.
[2]Habib,F.;Lin,P.-H.;Long,J.;Korobkov,I.;Wernsdorfer,W.;Murugesu,M.J.Am.Chem.Soc.2011,133:8830.