论文标题
固态磁簇的顺磁敏感性的半经验分析
A semi-empirical analysis of the paramagnetic susceptibility of solid state magnetic clusters
论文作者
论文摘要
新磁性材料合成的最新发展导致发现新的量子Paramagnet。这些材料中有许多，例如perovskites ba $ _ {4} $ lnmn $ _ {4} $ o $ $ $ _ {12} $（ln = sc或nb），ba $ _ {3} $ _ {3} $ mn $ _ {2} sr $ _ {3} $ cr $ _ {2} $ o $ _ {8} $存在具有较强的群集交互的孤立磁簇，但较弱局部能量尺度和磁性排序温度之间的这种偏移是磁挫败感的标志。在足够的高$ t $下，沮丧的集群磁体的顺磁敏感性（$χ$）可以适合居里 - 韦斯法律，但是通常不能将派生的显微镜参数与从其他方法获得的显微参数调和。在这项工作中，我们提出了一种分析显微镜理论，以获得二聚体和三聚体群磁体的$χ$，这是文献中最常见的两个，利用合适的海森伯格型汉密尔顿人。我们还以平均场级别添加了集群间的交互，从而在系统的临界温度中获得表达式，并定义了新的有效挫败参数$ f _ {\ text {eff}} $。通过处理某些选定材料的$χ$数据来说明我们的方法。
Recent developments in the synthesis of new magnetic materials lead to the discovery of new quantum paramagnets. Many of these materials, such as the perovskites Ba$_{4}$LnMn$_{4}$O$_{12}$ (Ln = Sc or Nb), Ba$_{3}$Mn$_{2}$O$_{8}$, and Sr$_{3}$Cr$_{2}$O$_{8}$ present isolated magnetic clusters with strong intracluster interactions but weak intercluster interactions, which delays the onset of order to lower temperatures ($T$). This offset between the local energy scale and the magnetic ordering temperature is the hallmark of magnetic frustration. At sufficient high-$T$, the paramagnetic susceptibility ($χ$) of frustrated cluster magnets can be fit to a Curie-Weiss law, but the derived microscopic parameters cannot in general be reconciled with those obtained from other methods. In this work, we present an analytical microscopic theory to obtain $χ$ of dimer and trimer cluster magnets, the two most commonly found in literature, making use of suitable Heisenberg-type Hamiltonians. We also add intercluster interactions in a mean-field level, thus obtaining an expression to the critical temperature of the system and defining a new effective frustration parameter $f_{\text{eff}}$. Our method is exemplified by treating the $χ$ data of some selected materials.
