Table-like magnetocaloric effect and high magnetocaloric response in Gd-Mn-Fe-Al amorphous/crystalline dual-phase system

In this work, a series of Gd-based amorphous/crystalline dual-phase composite materials are prepared by adjusting the Gd content in Gd-Mn-Fe-Al system. The Gd80(MnFeAl2)20 alloy exhibits a wide table-like magnetocaloric curve in the temperature range of 140 K to 260 K, with a peak value of 3.9 J kg−1 K−1 under a magnetic field change of 5 T. The wide table-like magnetocaloric effect is due to the dual-phase structure with the appropriate fraction ratio of amorphous matrix to crystalline phase, the nano-sized crystalline phase, spin-glass phase, second-order magnetic transition, and modest Curie temperature difference between two phases. All Gd-Mn-Fe-Al alloys possess the extremely wide working temperature spans. This, combining with the comparable magnetic entropy changes, leads to their high magnetocaloric responses. Our research not only develops the alloys with the excellent magnetocaloric properties, but also provides a feasible way to prepare the alloy with an extremely wide table-like magnetocaloric curve.