Phase transition-induced magnetocaloric effects in R2Mo2O7 (RÂ =Â Er, Dy, Gd and Y) molybdates

We have investigated the magnetic properties and magnetocaloric effects (MCEs) of R2Mo2O7 (R = Er, Dy, Gd and Y). Magnetic ground states of R2Mo2O7 largely depend on the radius of rare earth ion. Er2Mo2O7, Dy2Mo2O7 and Y2Mo2O7 with small rare earth radius exhibit spin-glass state around 20 K, while Gd2Mo2O7 with larger rare earth radius undergoes a ferromagnetic state below 78 K and a reentrant spin-glass behavior below 34 K. Magnetic phase transition leads to magnetocaloric effect. In particular, a natural table-like -ΔSM and a very large refrigerant capacity (RC) value of 94.4 J/kg was observed in a field change of 0-10.5 kOe for Gd2Mo2O7 due to two successive magnetic transitions at ∼78 and ∼10 K. These notable magnetocaloric properties make the Gd2Mo2O7 a potential candidate for low-field Ericsson-cycle magnetic refrigeration in the low temperature range.