论文标题
NAMN $ _2 $ o $ _4 $和li $ _ {0.92} $ Mn $ _2 $ _2 $ o $ $ _4 $的中子粉衍射研究
Neutron powder diffraction study of NaMn$_2$O$_4$ and Li$_{0.92}$Mn$_2$O$_4$: New insights on spin-charge-orbital ordering
论文作者
论文摘要
高压合成的准二维化合物NAMN $ _2 $ o $ _4 $和li $ _ {0.92} $ _2 $ _2 $ _2 $ o $ _4 $都是抗fiferromagnetic绝缘子，在这里使用中子的原子和磁性结构进行了中子和磁性结构的研究。 NAMN2O4的当前晶体结构分析表明，即使在低温下（降至1.5 K），MN3+/MN4+电荷订购状态也存在。由于Jahn-Teller效应，从MN的一个站点之一可以明显看出，MN3+八面体的强烈扭曲。在Tn = 39 K上方，观察到二维短距离相关性，如不对称弥漫性散射所示。在TN下面，观察到两个抗铁磁过渡（i）相应的长距离MN3+旋转顺序低于39 K，以及（ii）不一致的MN4+旋转订购以下10 k以下。相称的磁性结构（KC = 0.5，-0.5，0.5）遵循磁性型磁性Anissotration A Incoment A Incommers os Axes a gromant os of Axess ncormers os Axess os over AxeS; KIC =（0,0,0.216）的自旋密度波顺序。对于Li $ _ {0.92} $ Mn $ _2 $ o $ _4 $，另一方面，确认没有远距离旋转的订购状态降至1.5 K。
The high-pressure synthesized quasi-one-dimensional compounds NaMn$_2$O$_4$ and Li$_{0.92}$Mn$_2$O$_4$ are both antiferromagnetic insulators, and here their atomic and magnetic structures were investigated using neutron powder diffraction. The present crystal structural analyses of NaMn2O4 reveal that Mn3+/Mn4+ charge-ordering state exist even at low temperature (down to 1.5 K). It is evident from one of the Mn sites shows a strongly distorted Mn3+ octahedra due to the Jahn-Teller effect. Above TN = 39 K, a two-dimensional short-range correlation is observed, as indicated by an asymmetric diffuse scattering. Below TN, two antiferromagnetic transitions are observed (i) a commensurate long-range Mn3+ spin ordering below 39 K, and (ii) an incommensurate Mn4+ spin ordering below 10 K. The commensurate magnetic structure (kC = 0.5, -0.5, 0.5) follows the magnetic anisotropy of the local easy axes of Mn3+, while the incommensurate one shows a spin-density-wave order with kIC = (0,0,0.216). For Li$_{0.92}$Mn$_2$O$_4$, on the other hand, absence of a long-range spin ordered state down to 1.5 K is confirmed.
