混合价态钴ludwi-x的低激发磁态
Low lying magnetic states of the mixed valence cobalt ludwigite
摘要：
对混合价态均金属硼镁石Co_3O_2BO_3和Fe_3O_2BO_3的不同结构和磁性有两种解释。其中之一将物理行为与阳离子之间的电荷有序过程联系起来，这在简单的氧化物中是众所周知的。另一种将这种效应归因于局部成对磁相互作用。最近对铁路德维希体系的第一性原理计算表明，结构阳离子二聚化是由于形成了强磁性二联体，支持第二种模型。在这里，我们证实了磁相互作用的主导地位，以解释在钴化合物中没有二聚化。采用密度泛函方法对Co_3O_2BO_3的非共线自旋进行了计算，确定了其低温磁序.低自旋被发现在三价钴网站，从而防止形成的铁磁二分体，有利于在Fe 3 O2 BO 3二聚的机制。我们得出结论，高自旋Fe 3+和低自旋Co 3+成对相互作用之间的差异是负责观察到的两种化合物之间的差异。两两磁相互作用也解释了低温体AF态在Fe ludwikide中的存在和在Co材料中的不存在之间的差异。
英文摘要：
There are two interpretations offered for the different structural and magnetic properties of the mixed valence homo-metallic ludwigites, Co3O2BO3 and Fe3O2BO3. One of them associates the physical behavior to charge ordering processes among the cations, as is well known in simpler oxides. The other attributes the effects to local pairwise magnetic interactions. Recently first principles calculations in the iron ludwigite have shown that the structural cation dimerization is due to the formation of strong magnetic dyads supporting the second model. Here we confirm the dominance of magnetic interactions to explain the absence of dimerization in the cobalt compound. Density functional non-collinear spin calculations are carried out on Co3O2BO3 to determine its low temperature magnetic order. Low spin is found on tri-valent cobalt sites, thus preventing the formation of the ferromagnetic dyad, the mechanism which favors dimerization in Fe3O2BO3. We conclude that the difference between high spin Fe3+ and low spin Co3+ pairwise interactions is responsible for the observed differences between the two compounds. The pairwise magnetic interactions also explain the difference between the existence of low temperature bulk AF state in the Fe ludwigite and its absence in the Co material.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
