标题： Kagome金属UNb$_6$Sn$_6$的磁序和物理性质 显示英文标题

标题： Magnetic order and physical properties of the Kagome metal UNb$_6$Sn$_6$

摘要： 材料$RM_6X_6$家族（$R$ = 稀土，$M$ = 过渡金属，$X$ = Ga， Si， Ge， Sn）由于其过渡金属原子的Kagome网络、局域磁各向异性以及广泛的化学可调性，产生了一系列涌现现象，如电荷密度波、本征霍尔效应和复杂的磁序。在这里，我们报告了一种新的“166”材料，其中包含一种锕系元素（铀）和一种4$d$过渡金属（铌），以研究5$f$-4$d$电子166系统的性质。 UNb$_6$Sn$_6$在六方$P$6/$mmm$空间群中结晶，由于沿$c$轴的类似 CoSn 的笼状结构尺寸发生变化，导致存在一定程度的无序。 在零磁场下冷却时，材料在$T_\mathrm{2}$= 46 K 和$T_\mathrm{N}$= 43 K 处经历两次磁相变。低温零场相是一种反铁磁体，具有有序的铀磁矩和由中子衍射确定的$\textbf{k}$=(0,0,1/2) 传播矢量。 备注中，当磁场沿$c$轴施加时，在磁矩在2 K和$\ge$13.6 T下饱和于2.62${\mu}_{\mathrm{B}}$/U之前，通过磁化率和电阻率数据观察到五次额外的磁性转变。在两个磁相区域中，UNb$_6$Sn$_6$的霍尔电阻率显著偏离磁化率，表明这些相具有大的贝里曲率或费米面的变化。 未知磁场依赖相的磁序 UNb$_6$Sn$_6$表明了5$f$-4$d$166系统的复杂性，并鼓励进一步研究其性质。 显示英文摘要

摘要： The $RM_6X_6$ family of materials ($R$ = rare-earth, $M$ = transition metal, $X$ = Ga, Si, Ge, Sn) produces an array of emergent phenomena, such as charge density waves, intrinsic Hall effects, and complex magnetic order, due to its Kagome net of transition metal atoms, its local-moment magnetic anisotropies, and its extensive chemical tunability. Here, we report a new ``166" material containing both an actinide (uranium) and a 4$d$ transition metal (niobium) to investigate the properties of a 5$f$-4$d$ electron 166 system. UNb$_6$Sn$_6$ crystallizes in the hexagonal $P$6/$mmm$ space group with a small degree of disorder due to shifts in the size of the CoSn-like cages along the $c$ axis. Upon cooling at zero magnetic field, the material undergoes two magnetic phase transitions at $T_\mathrm{2}$ = 46 K and $T_\mathrm{N}$ = 43 K. The low-temperature, zero-field phase is an antiferromagnet with ordered uranium moments and a $\textbf{k}$=(0,0,1/2) propagation vector determined by neutron diffraction. Remarkably, with a magnetic field applied along the $c$ axis, five additional magnetic transitions occur, evidenced by magnetization and resistivity data, before the moment saturates at 2.62 ${\mu}_{\mathrm{B}}$/U at 2 K and $\ge$13.6 T. In two magnetic phase regions, the Hall resistivity of UNb$_6$Sn$_6$ significantly deviates from the magnetization, suggesting that the phases have a large Berry curvature or a change in the Fermi surface. The unknown magnetic ordering of the field-dependent phases of UNb$_6$Sn$_6$ demonstrates the complexity of the 5$f$-4$d$ 166 system and encourages further study of its properties.