Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970 Porto Alegre, Brazil.
J Phys Condens Matter. 2010 Dec 15;22(49):496004. doi: 10.1088/0953-8984/22/49/496004.
We report new results on the magnetic properties of the FexCo1 - xTa2O6 series of compounds. Essentially using neutron-diffraction and magnetic measurements we study, in more detail, the low-x limit of the temperature versus x phase diagram, where a new bicritical point is observed. The complete phase diagram shows three different magnetic phases at low temperature, for a high, intermediate and very low iron content. These phases consist of distinct antiferromagnetic orderings, characterized by different pairs of propagation vectors. We obtain information about the intraplane exchange interactions by fitting a high-temperature series of the magnetic susceptibility. Here we improve on a previously employed model, showing that two non-equivalent next-nearest-neighbor interactions must be taken into account in order to allow for in-plane magnetic orderings that are consistent with the neutron-diffraction results.
我们报告了 FexCo1 - xTa2O6 系列化合物的磁性的新结果。我们主要使用中子衍射和磁性测量，更详细地研究了温度与 x 相图的低 x 极限，在该极限处观察到了一个新的双临界点。完整的相图在低温下显示出三种不同的磁性相，对于高、中和非常低的铁含量。这些相由不同的传播矢量特征的不同的反铁磁有序组成。我们通过拟合高温下的磁化率系列获得了关于面内交换相互作用的信息。在这里，我们改进了以前使用的模型，表明为了允许与中子衍射结果一致的面内磁有序，必须考虑两个非等效的次近邻相互作用。
