Achievement of giant cryogenic refrigerant capacity in quinary rare-earths based high-entropy amorphous alloy

Magnetic refrigeration（MR） by utilizing the magnetocaloric（MC） effect is recognized as one of the most potential promising solid state environmentally friendly and high efficiency alternative method to the well-used state-of-the-art gas compression cooling technique.In this work,a systematic investigation of quinary equi-atomic rare-earths（RE） based Er20Ho2 OGd20Ni20CO20 high-entropy（HE） amorphous alloy in terms of the microstructure,magnetic and magnetocaloric（MC） properties have been reported.The Er20Ho20Gd20Ni20Co20 exhibits promising glass forming ability with an undercooled liquid region of 72 K.Excellent cryogenic MC performances can be found in wide temperature from ～25 and ～75 K,close to H2 and N2 liquefaction,respectively.Apart from the largest magnetic entropy change（-△SM） reaches17.84 J/（kg K） with 0-7 T magnetic field change,corresponding refrigerant capacity（RC） attains a giant value of 1030 J/kg.The promising cryogenic MC performances together with the unique HE amorphous characterizations make the quinary Er20Ho20Gd20Ni20Co20 HE amorphous alloy attractive for cryogenic MR applications.