Magnetocaloric properties of Gd2MoO6 prepared by a simple and fast method

Abstract The experimental study of the specific heat, magnetic susceptibility, and magnetization of Gd2MoO6 powder sample was performed in the temperature range between 0.4 K and 300 K in the magnetic fields up to 9 T. Powder sample was prepared via nonconventional mechanochemical/thermal process from powdered oxide precursors. Magnetic ion Gd3+ with spin S = 7/2 is responsible for the magnetic properties. The specific heat study in zero magnetic field revealed two anomalies; a phase transition to the ordered state at TN1 ≈ 0.98 K and a smaller maximum at TN2 ≈ 0.6 K. Relatively high magnetic density 6.85 g/cm3 of Gd2MoO6 predetermines this compound as potential magnetocaloric material with a high cooling performance at cryogenic temperatures. A large conventional magnetocaloric effect was found around 3 K with magnetic entropy change −ΔSmax ≈ 44 J/(kg K) (300 mJ/(Kcm3)) for magnetic field change from 9 T down to zero with a refrigerant capacity of 464 J/kg. Maximal temperature change -ΔTad ≈ 23.8 K was found for initial temperature Tinit ≈ 29.9 K for the mentioned change of magnetic field. Alternating susceptibility measurements revealed the presence of two relaxation channels in Gd2MoO6 existing in two different time scales ≈ 10-3 s and ≈ 1 s.