The physical properties of Gd3Ru: A real candidate for a practical cryogenic refrigerator

Abstract

The magnetization, the specific heat, and the magnetocaloric effect (MCE) for Gd3Ru are presented as function of temperature at different magnetic fields. The results show a maximum entropy change −ΔS= 30 J/kg K @ 5 T, which is the highest value for the R3M compounds. With a non-hysteretic transition of first order type at TC = 54 K, it presents a temperature change ΔTmax = 5.7 K around 59 K with a refrigerating cooling power of 700 J/kg and these results are comparable to values found for giant MCE materials. This compound is stable and able to operate at temperatures between 90 K and 40 K with a minimum −ΔS= 5 J/kg K. These figures were obtained by sweeping the magnetic field without using sample preparation routines. This methodology is appropriate to evaluate the MCE for the cycling process of a cryogenic magnetic refrigerator.

Excellent magnetocaloric properties in RE2Cu2Cd (RE = Dy and Tm) compounds and its composite materials

“…Recently, the rare-earth ( RE ) based alloys and oxides, which exhibit the large reversible MCEs and refrigeration capacity with small or zero hysteresis have been of great of interest 11 12 13 14 15 16 17 . Increasing efforts have been devoted for study of the ternary intermetallic compounds of the RE 2 T 2 X 2:2:1 ( T = transition metals, and X = III group p-metals).…”

Effect of Dy substitution in the giant magnetocaloric properties of HoB2

“…Similarly, Ho 0.3 Dy 0.7 B 2 has almost the same |Δ S M MAX | as HoNi [ 34 , 35 ], however with a much larger |Δ T ad MAX |. In the case of DyB 2 , even though it shows almost half of |Δ S M | compared to Gd 3 Ru [ 36 ], its |Δ T ad MAX | is higher and comparable to DyAl 2 [ 37 ], although both of them are lower than Er 0.53 Ho 0.47 Co 2 [ 38 , 39 ]. Furthermore, the TEC in Ho 1- x Dy x B 2 alloys tends to be relatively robust for a higher value of Δ T lift , due to the multiple transition nature in these materials.…”

Magnetocaloric materials for hydrogen liquefaction

“…For instance, the Curie temperature of Gd 3 Co can be lowered after Ru incorporation in the Gd 3 Co x Ru 1-x . 113,114 Alternatively, the solid solution between Er and Gd allows a great tunability of the transition temperature in Er 3-x Gd x Co. 115 There are more compounds with R 3 M stoichiometry and most of them have not been systematically studied for magnetocaloric applications. Even so, there are a few promising examples like Gd 3 Ru, whose Curie temperature is 54 K and displays a remarkable MCE with values up to 30 J kg −1 K −1 for 5 T. 116 Again, the solid solution between Gd and Er can be used to adjust the Curie temperature with remarkable precision.…”