Table-like magnetocaloric effect and large refrigerant capacity in Nd6Fe13Pd1-xAgx compounds

Abstract Table-like magnetocaloric effect is significant for using the Ericsson cycle in the applications of magnetic refrigeration above 20 K. A series of Nd6Fe13Pd1-xAgx (x = 0.1, 0.2, 0.3, 0.4) compounds were prepared by the arc-melting method, showing a single crystalline phase in the tetragonal Nd6Fe13Si-type structure with the space group I4/mcm. All of the compounds undergo a first-order magnetic transition from the ferromagnetism to antiferromagnetism with the temperature increases, as well as a metamagnetic transition from antiferromagnetic state to ferromagnetic state induced by an applied field. The table-like magnetocaloric effects with large refrigerant capacities in these compounds have been observed, which is very rare in a single phase. A constant ΔSM in a temperature span of 60 K in the Nd6Fe13Pd0.6Ag0.4 compound can be observed. For a field change of 0–5 T, the peak values of |ΔSM| for the Nd6Fe13Pd0.9Ag0.1, Nd6Fe13Pd0.8Ag0.2, Nd6Fe13Pd0.7Ag0.3 and Nd6Fe13Pd0.6Ag0.4 compounds are estimated to be 4.9 J kg−1 K−1, 4.5 J kg−1 K−1, 3.5 J kg−1 K−1 and 3.4 J kg−1 K−1 with the corresponding refrigerant capacity values of 327 J kg−1, 315 J kg−1, 306 J kg−1 and 289 J kg−1, respectively. The table-like magnetocaloric effect and large working temperature spans make the series of compounds a good candidate for single-phase magnetic refrigeration material at low temperature based on the Ericsson cycle.