Observation of a secondary slow relaxation process for the field-induced single-molecule magnet U(H2BPz2)3.
Observation of a secondary slow relaxation process for the field-induced single-molecule magnet U(H2BPz2)3.
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DOI：
10.1021/ja1009019
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发表时间：
2010-05
影响因子：
15
通讯作者：
Jeffrey D. Rinehart;Katie R. Meihaus;J. Long
中科院分区：
文献类型：
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作者：
Jeffrey D. Rinehart;Katie R. Meihaus;J. Long
通过单晶X射线衍射和交流磁化率测量对三角棱柱配合物U（H（2）BPz（2））（3）进行了表征。交流磁化率数据表明，存在多个过程负责缓慢的磁弛豫。在500-5000 Oe的直流磁场中，在1和1500 Hz之间的交流开关频率下观察到的异相信号表明热弛豫势垒为ca。8厘米（-1）的分子，与温度无关的过程接管在最低温度探测。值得注意的是，一个前所未有的，较慢的弛豫过程变得明显的交流开关频率在0.06和1 Hz之间，其中的弛豫时间与施加的直流电场的单调增加表明一个直接的弛豫路径。
The trigonal prismatic complex U(H(2)BPz(2))(3) is characterized by single crystal X-ray diffraction and ac magnetic susceptibility measurements. The ac susceptibility data demonstrate the presence of multiple processes responsible for slow magnetic relaxation. Out-of-phase signals observed at ac switching frequencies between 1 and 1500 Hz in dc fields of 500-5000 Oe indicate a thermal relaxation barrier of ca. 8 cm(-1) for the molecule, with a temperature-independent process taking over at the lowest temperatures probed. Significantly, an unprecedented, slower relaxation process becomes apparent for ac switching frequencies between 0.06 and 1 Hz, for which a monotonic increase of the relaxation time with an applied dc field suggests a direct relaxation pathway.