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.

• Received 4 February 2024
• Revised 17 April 2024
• Accepted 22 April 2024

DOI:https://doi.org/10.1103/PhysRevB.109.184413