论文标题
抗铁磁性氧化剂和氟非磁性物质中的自旋动力学：Lamnaso，Lamnsbo和Bamnasf
Spin Dynamics in the Antiferromagnetic Oxypnictides and Fluoropnictides: LaMnAsO, LaMnSbO, and BaMnAsF
论文作者
论文摘要
在线性自旋理论的框架中，使用$ J_1-J_2-J_C $ HEISENBERG模型分析了来自多晶抗磁性LAMNASO，LAMNSBO和BAMNASF的非弹性中子散射（INS）。所有三个系统都均均清楚地表明，在MN方格晶格层（$ j_1 $和$ j_2 $）中最近的最接近和下一期邻里相互作用都是抗fiferromagnetic（AFM）。但是，对于所有研究的化合物，竞争互动的比率为$ 2J_2/j_1 <1 $，它有利于方格核心棋盘AFM结构而不是条纹AFM结构。所有三个系统中的平面间耦合$ j_c $均为$ \ sim 3 \ sim 3 \ times10^{ - 4} j_1 $，呈现具有准二维字符的这些系统的磁性属性。 SB的替换为显着降低面内交换耦合，这也反映在n {é} El温度的降低中，$ t _ {\ rm n} $。尽管BAMNASF以Lamnaso为单位，但它们的J_1 $和$ J_2 $的值大不相同。使用密度函数理论，我们计算交换参数$ j_ {ij} $合理化这些系统之间的差异。
Inelastic neutron scattering (INS) from polycrystalline antiferromagnetic LaMnAsO, LaMnSbO, and BaMnAsF are analyzed using a $J_1-J_2-J_c$ Heisenberg model in the framework of the linear spin-wave theory. All three systems show clear evidence that the nearest- and next-nearest-neighbor interactions within the Mn square lattice layer ($J_1$ and $J_2$) are both antiferromagnetic (AFM). However, for all compounds studied the competing interactions have a ratio of $2J_2/J_1 < 1$, which favors the square lattice checkerboard AFM structure over the stripe AFM structure. The inter-plane coupling $J_c$ in all three systems is on the order of $\sim 3\times10^{-4}J_1$, rendering the magnetic properties of these systems with quasi-two-dimensional character. The substitution of Sb for As significantly lowers the in-plane exchange coupling, which is also reflected in the decrease of the N{é}el temperature, $T_{\rm N}$. Although BaMnAsF shares the MnAs sheets as LaMnAsO, their $J_1$ and $J_2$ values are substantially different. Using density functional theory, we calculate exchange parameters $J_{ij}$ to rationalize the differences among these systems.
