Magnetism and giant magnetocaloric effect in rare-earth-based compounds R 3BWO9 (R = Gd, Dy, Ho)* *Project supported by the National Natural Science Foundation of China (Grant Nos. U1832209, 11874336, and 11904003), the National Basic Research Program of China (Grant No. 2016YFA0300103), the Innovative Program of Hefei Science Center CAS (Grant No. 2019HSC-CIP001), and the Natural Science Foundation of Anhui Province,

Abstract

The magnetism and magnetocaloric effect (MCE) of rare-earth-based tungstate compounds R 3BWO9 (R = Gd, Dy, Ho) have been studied by magnetic susceptibility, isothermal magnetization, and specific heat measurements. No obvious long-range magnetic ordering can be found down to 2 K. The Curie–Weiss fitting and magnetic susceptibilities under different applied fields reveal the existence of weak short-range antiferromagnetic couplings at low temperature in these systems. The calculations of isothermal magnetization exhibit a giant MCE with the maximum changes of magnetic entropy being 54.80 J/kg⋅K at 2 K for Gd3BWO9, 28.5 J/kg⋅K at 6 K for Dy3BWO9, and 29.76 J/kg⋅K at 4 K for Ho3BWO9, respectively, under a field change of 0–7 T. Especially for Gd3BWO9, the maximum value of magnetic entropy change () and adiabatic temperature change () are 36.75 J/kg⋅K and 5.56 K for a low field change of 0–3 T, indicating a promising application for low temperature magnetic refrigeration.