Uranium(IV) 5f2 magnetism is dominated by a transition from a triplet to a singlet ground state at low temperatures. For the first time, we achieved magnetic ordering of U(IV) atoms in a complex fluoride through the incorporation of 3 d transition metal cations. This new route allowed us to obtain an unprecedented series of U(IV) ferrimagnetic materials of the new composition Cs2MU3F16 (M = Mn2+, Co2+, and Ni2+), which were comprehensively characterized with respect to their structural and magnetic properties. Magnetic susceptibility measurements revealed ferromagnetic-like phase transitions at temperatures of ∼14.0, 3.5, and 4.8 K for M = Mn2+, Co2+, and Ni2+, respectively. The transition is not observed when the magnetic M cations are replaced by a diamagnetic cation, Zn2+. Neutron diffraction measurements revealed the magnetic moments of 0.91(6)-1.97(3) μB on the U atoms, which are only partially compensated by antiparallel moments of 1.53(14)-3.26(5) μB on the 3 d cations. This arrangement promotes suppression of the transition to a diamagnetic ground state characteristic of U(IV), and in doing so, induces magnetic ordering on uranium via 3 d-5 f exchange coupling.

中文翻译：

---

U(IV) 原子上的 3d 金属诱导磁性排序作为通向 U(IV) 磁性材料的途径

铀 (IV) 5f2 的磁性主要是在低温下从三重态到单重态基态的转变。我们首次通过掺入 3 d 过渡金属阳离子实现了复合氟化物中 U(IV) 原子的磁性排序。这条新路线使我们能够获得一系列前所未有的 U(IV) 亚铁磁材料，其新组成为 Cs2MU3F16（M = Mn2+、Co2+ 和 Ni2+），这些材料在结构和磁性方面得到了全面的表征。磁化率测量显示，对于 M = Mn2+、Co2+ 和 Ni2+，分别在~14.0、3.5 和 4.8 K 的温度下发生类铁磁相变。当磁性 M 阳离子被抗磁性阳离子 Zn2+ 取代时，没有观察到这种转变。中子衍射测量揭示了 0 的磁矩。U 原子上的 91(6)-1.97(3) μB，仅部分被 3 d 阳离子上的 1.53(14)-3.26(5) μB 的反平行矩补偿。这种安排促进了对 U(IV) 的抗磁性基态特征的转变的抑制，并且在这样做时，通过 3 d-5 f 交换耦合在铀上诱导磁性排序。