论文标题
CA $ _2 $ ru $ _ {1-x} $ fe $ _x $ o $ $ _4 $的三维磁性阶段的竞争
Competition of three-dimensional magnetic phases in Ca$_2$Ru$_{1-x}$Fe$_x$O$_4$: A structural perspective
论文作者
论文摘要
CA $ _2 $ RU $ _ {1-x} $ fe $ _x $ o $ $ _4 $（x = 0.02，0.02，0.05，0.08和0.12）的结晶和磁性结构已使用中子和X射线衍射进行了研究。 Fe掺杂可在顶端和平面方向上降低Ru-O键长。较小的ru（fe）o $ _6 $八面体导致其减少失真。 $ pbca $太空集团在所有的Fe培养产品中都保持着，八面体扁平也是如此。变暖对晶格的影响与释放扭曲的八面体的Fe掺杂的作用相似，但是在N $ \急性{E} $ EL温度附近会突然突然八面体伸长。已经观察到了两个相互竞争的反铁磁订单，$ a $和$ b $的阶段。 Fe掺杂的晶体结构更喜欢后者。随着掺杂的增加，以$ b $的相位相位，以$ A $ A的成本持续增长，最终以x = 0.12取代它。在磁过渡温度以上的二维抗磁性临界波动的缺失以及低于过渡的三维磁相关，以及异常的晶格响应，表明轨道自由度在驱动磁相竞争中的重要作用。
The crystalline and magnetic structures of Ca$_2$Ru$_{1-x}$Fe$_x$O$_4$ (x=0.02, 0.05, 0.08 and 0.12) have been studied using neutron and X-ray diffraction. The Fe-doping reduces the Ru-O bond length in both apical and planar directions. The smaller Ru(Fe)O$_6$ octahedron leads to its reduced distortion. The $Pbca$ space group is maintained in all the Fe-dopings, so is the octahedral flattening. Warming has a similar effect on the lattice to that of the Fe-doping in releasing the distorted octahedra but precipitates an abrupt octahedral elongation near the N$\acute{e}$el temperature. Two competing antiferromagnetic orders, $A$- and $B$-centered phases have been observed. The Fe-doping-relaxed crystal structure prefers the latter to the former. As the doping increases, the $B$-centered phase continuously grows at the cost of the $A$-centered one and eventually replaces it at x=0.12. The absence of the two-dimensional antiferromagnetic critical fluctuations above the magnetic transition temperature and the three-dimensional magnetic correlation below the transition, together with the anomalous lattice response, point to an important role of orbital degree of freedom in driving the magnetic phase competition.
