Cryogenic magnetocaloric effect in R2GeMoO8 (R = Gd and Dy) compounds

The cryogenic magnetocaloric effect has attracted great attention due to its application in cryogenic refrigeration technology, which is essential for space science and quantum computing. In this study, the magnetocaloric effect of Gd2GeMoO8 (GGMO) and Dy2GeMoO8 (DGMO), which were prepared by simple solid-state reactions, had been investigated. The XRD refinement analysis suggested that GGMO and DGMO crystallize in a tetragonal structure. A large magnetic entropy change (ΔSM) of −41.2 J kg−1 K−1 was observed at 1.8 K for GGMO under a magnetic field (ΔH) of 7 T. A moderate ΔSM of −14.1 J kg−1 K−1 was obtained at 4.5 K under a ΔH of 7 T in DGMO. The refrigeration capacity and relative cooling power reached 257.4 and 337.8 J kg−1 for GGMO and 133.3 and 143.7 J kg−1 for DGMO, respectively, under a ΔH of 0–7 T. Our results suggest that GGMO is a competitive cryogenic magnetic refrigeration material.