Centre for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Århus C, Denmark.
Inorg Chem. 2011 Feb 21;50(4):1441-6. doi: 10.1021/ic102008a. Epub 2011 Jan 19.
Ni(HCOO)(2)(H(2)O)(2) is a structurally simple coordination polymer showing interesting magnetic phase transitions at low temperature (<16K). Previously published studies of these phase transitions have yielded inconsistent results, questioning the correctness of the published magnetic structure. Here heat capacity and magnetic susceptibility of a fully, a partly and a non-deuterated sample were measured, and they all exhibit magnetic phase transitions around 3 and 15 K. Neutron powder diffraction data was collected on the fully deuterated sample at various temperatures between 1.5 and 25 K. A magnetic model was refined against the neutron diffraction data using a spin system composed of two canted antiferromagnetic sublattices. The magnetic moments of the two sublattices show different magnitude, 1.7 μ(B) and 1.3 μ(B), and the temperature dependence of the magnetic sublattices is quite different. One of the sublattices shows the expected temperature behavior of an antiferromagnetic compound whereas the other sublattice follows a Brillouin like function with a slowly increasing magnetization below the Néel temperature.
Ni(HCOO)2(H2O)2 是一种结构简单的配位聚合物，在低温（<16K）下表现出有趣的磁相变。先前对这些相变的研究得到了不一致的结果，这使得发表的磁结构的正确性受到质疑。在这里，我们测量了完全、部分和非氘代样品的热容和磁化率，它们都在 3 和 15 K 左右表现出磁相变。在 1.5 到 25 K 之间的不同温度下，我们对完全氘代样品进行了中子粉末衍射数据采集。使用由两个倾斜反铁磁亚晶格组成的自旋系统，根据中子衍射数据对磁模型进行了细化。两个亚晶格的磁矩显示出不同的大小，1.7 μ(B)和 1.3 μ(B)，并且磁亚晶格的温度依赖性非常不同。一个亚晶格表现出反铁磁化合物的预期温度行为，而另一个亚晶格在尼尔温度以下遵循类似布里渊的函数，磁化率缓慢增加。
