We report a new nickel hydroxyfluoride diaspore Ni(OH)F prepared using hydrothermal synthesis from NiCl₂·6H₂O and NaF. Magnetic characterization reveals that, contrary to other reported transition-metal hydroxyfluoride diaspores, Ni(OH)F displays weak ferromagnetism below the magnetic ordering temperature. To understand this difference, neutron diffraction is used to determine the long-range magnetic structure. The magnetic structure is found to be distinct from those reported for other hydroxyfluoride diaspores and shows an antiferromagnetic spin ordering in which ferromagnetic canting is allowed by symmetry. Furthermore, neutron powder diffraction on a deuterated sample, Ni(OD)F, reveals partial anion ordering that is distinctive to what has previously been reported for Co(OH)F and Fe(OH)F. Density functional theory calculations show that OH/F ordering can have a directing influence on the lowest energy magnetic ground state. Our results point toward a subtle interplay between the sign of magnetic exchange interactions, the electronic configuration, and anion disordering.

中文翻译：

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电子构型和阴离子有序性对羟基氟化物水硬铝石磁性行为的相互作用


我们报道了一种新型羟基氟化镍水硬铝石Ni(OH)F，其由NiCl ₂ ·6H ₂ O和NaF水热合成制备。磁性表征表明，与其他报道的过渡金属羟基氟化物硬水铝石相反，Ni(OH)F 在磁有序温度以下表现出弱铁磁性。为了了解这种差异，使用中子衍射来确定远程磁结构。发现磁性结构与报道的其他羟基氟化物硬水铝石的磁性结构不同，并且显示出反铁磁自旋排序，其中对称性允许铁磁倾斜。此外，氘化样品 Ni(OD)F 上的中子粉末衍射揭示了部分阴离子排序，这与之前报道的 Co(OH)F 和 Fe(OH)F 不同。密度泛函理论计算表明，OH/F 排序可以对最低能量磁基态产生直接影响。我们的结果表明磁交换相互作用的符号、电子构型和阴离子无序之间存在微妙的相互作用。