The rare-earth (RE) based Shastry-Sutherland lattice (SSL) materials have attracted recent attention for exploring the exotic magnetic phases of $4f$ electrons. Here, we present a comparative study on low-temperature magnetization and specific-heat results of two tetragonal structure compounds ${RE}_2\mathrm{B}{\mathrm{e}}_2\mathrm{Ge}{\mathrm{O}}_7$ ($RE=\mathrm{Pr}$, Nd), where the non-Kramers $\mathrm{P}{\mathrm{r}}^{3+}$ ($J=4$) ions and Kramers $\mathrm{N}{\mathrm{d}}^{3+}$ ($J=9/2$) ions are located on the SSL geometry with “AA”-type stacking fashion along the [001] axis. Temperature-dependent magnetic susceptibility and isothermal field-dependent magnetization $M$($B$) measurements reveal that these two compounds share a similar Ising-like magnetic anisotropy with easy magnetization along the [001] axis and additional fourfold symmetry within the $ab$ plane. For their magnetic ground states, $\mathrm{N}{\mathrm{d}}_2\mathrm{B}{\mathrm{e}}_2\mathrm{Ge}{\mathrm{O}}_7$ exhibits the coexistence of short-range spin correlation and long-range magnetic order with $T_{\mathrm{N}}=0.26$ K in zero magnetic field, while $\mathrm{P}{\mathrm{r}}_2\mathrm{B}{\mathrm{e}}_2\mathrm{Ge}{\mathrm{O}}_7$ does not show any signature of long-range magnetic ordering at temperatures as low as 0.08 K. The ac susceptibility and specific-heat analysis of $\mathrm{P}{\mathrm{r}}_2\mathrm{B}{\mathrm{e}}_2\mathrm{Ge}{\mathrm{O}}_7$ reveal a dynamic spin-freezing behavior below ∼0.22 K similar to that observed in Pr-based pyrochlore spin-ice systems.

中文翻译：

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Shastry-Sutherland 晶格材料中不同的磁性基态：Pr2Be2GeO7 与 Nd2Be2GeO7

基于稀土 (RE) 的 Shastry-Sutherland 晶格 (SSL) 材料最近因探索稀土磁性相而引起了人们的关注。$4F$电子。在这里，我们对两种四方结构化合物的低温磁化强度和比热结果进行了比较研究${右乙}_2\mathrm{乙}{\mathrm{e}}_2锗{\mathrm{氧}}_7$($右乙=\mathrm{普罗}$, Nd)，其中非克莱默$\mathrm{磷}{\mathrm{r}}^{3+}$($J=4$) 离子和克莱默$\mathrm{氮}{\mathrm{d}}^{3+}$($J=9/2$) 离子位于 SSL 几何结构上，沿 [001] 轴以“AA”型堆叠方式。与温度相关的磁化率和与等温场相关的磁化强度$\mathrm{中号}$($乙$）测量表明，这两种化合物具有类似的伊辛磁各向异性，易于沿 [001] 轴磁化，并且在$A乙$飞机。对于它们的磁性基态，$\mathrm{氮}{\mathrm{d}}_2\mathrm{乙}{\mathrm{e}}_2锗{\mathrm{氧}}_7$表现出短程自旋相关性和长程磁序的共存${\mathrm{时间}}_{\mathrm{氮}}=0.26$K 为零磁场，同时$\mathrm{磷}{\mathrm{r}}_2\mathrm{乙}{\mathrm{e}}_2锗{\mathrm{氧}}_7$在低至 0.08 K 的温度下，未显示任何长程磁有序特征。交流磁化率和比热分析$\mathrm{磷}{\mathrm{r}}_2\mathrm{乙}{\mathrm{e}}_2锗{\mathrm{氧}}_7$揭示了低于 ∼0.22 K 的动态自旋冻结行为，类似于在基于 Pr 的烧绿石自旋冰系统中观察到的行为。