Effect of Dy, Ho, and Er substitution on the magnetocaloric properties of Gd-Co-Al-Y high entropy bulk metallic glasses

Glass-forming ability, thermal stability and magnetocaloric properties of Gd25Co25Al25Y25 and Gd25Co25Al25Y15RE10 (RE = Dy, Ho, and Er) high entropy metallic glasses are evaluated. With the substitution of Y by adjacent heavy rare earth elements, i.e., Dy, Ho, or Er, the critical dimension (D-c), the width of the supercooled liquid region, magnetic entropy changes (vertical bar Delta S-M vertical bar) and refrigeration capacity (RC) increase obviously. However, the magnetic transition temperature (T-C) almost keeps constant around 40 K, which may be attributed to the exchange interaction between Y and transition metal or other rare earth elements. Among resulting Gd25Co25Al25Y15RE10 metallic glasses, the peak values of vertical bar Delta S-M vertical bar and RC can be improved from 6.76 to 7.35 Jkg(-1) K(-1)and 424 to 488 Jkg(-1) when substituting Dy by Ho. This makes Gd25Co25Al25Y15Ho10 as an attractive candidate for magnetic refrigerants in hydrogen liquefaction temperature range. (C) 2020 Elsevier B.V. All rights reserved.