Giant refrigerant capacity in Gd-based amorphous/nanocrsytalline composite fibers

Magnetic refrigeration attracts increasing interests for its superior efficiency and eco-friendliness. The crystalline magnetocaloric materials usually exhibit large entropy change (ΔSM) but narrow working temperature range, while the amorphous magnetocaloric materials usually exhibit broad working temperature range but skimpy ΔSM at low temperatures. Herein, we designed Gd90-xNixAl10 (x = 5–15) amorphous/nanocrystalline composite fibers (ANCF) using melt extraction method in order to combine the advantages of amorphous and crystalline magnetocaloric materials. The Gd-based ANCF exhibits a giant refrigerant capacity (RC, 985 J kg-1 for Gd80Ni10Al10) across a wide temperature range from 70 K to 270 K that is much larger than the known magnetocaloric materials. This superior property is attributed to the ideal coupling between amorphous phase and crystalline Gd & [GdNi] phases that distribute homogeneously. This work provides not only promising refrigeration magnetic materials but also a general scaleable method for fabricating at the temperature range from room temperature to liquid nitrogen temperatures.