Peng Yan, Mereacre Valeriu, Anson Christopher E, Powell Annie K
Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany.
Phys Chem Chem Phys. 2016 Aug 3;18(31):21469-80. doi: 10.1039/c6cp02942f.
A [DyFeDy(μ3-OH)2(pmide)2(p-Me-PhCO2)6] coordination cluster, where pmideH2 = N-(2-pyridylmethyl)iminodiethanol, has been synthesized and the magnetic properties studied. The dc magnetic measurements reveal dominant antiferromagnetic interactions between the metal centres. The ac measurements reveal zero-field quantum tunnelling of the magnetisation (QTM) which can be understood, but not adequately modelled, in terms of at least three relaxation processes when appropriate static (dc) fields are applied. To investigate this further, (57)Fe Mössbauer spectroscopy was used and well-resolved nuclear hyperfine structures could be observed, showing that on the Mössbauer time scale, without applied field or else with very small applied fields, the iron nuclei experience three or more superhyperfine fields arising from the slow magnetisation reversal of the strongly polarized fields of the Dy(III) ions.
一种[DyFeDy(μ3-OH)2(pmide)2(p-Me-PhCO2)6]配位簇已被合成，其中pmideH2 = N-(2-吡啶甲基)亚氨基二乙醇，并对其磁性进行了研究。直流磁性测量揭示了金属中心之间主要的反铁磁相互作用。交流测量揭示了磁化强度的零场量子隧穿（QTM），当施加适当的静态（直流）场时，这可以根据至少三个弛豫过程来理解，但不能得到充分的建模。为了进一步研究这一点，使用了(57)Fe穆斯堡尔光谱，并且可以观察到分辨良好的核超精细结构，这表明在穆斯堡尔时间尺度上，在没有施加场或施加非常小的场的情况下，铁核经历了由Dy(III)离子强极化场的缓慢磁化反转产生的三个或更多的超超精细场。
