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 (Dc), the width of the supercooled liquid region, magnetic entropy changes (|ΔSM|) and refrigeration capacity (RC) increase obviously. However, the magnetic transition temperature (TC) 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 |ΔSM| and RC can be improved from 6.76 to 7.35 Jkg−1K−1and 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. •The Gd25Co25Al25Y25 and Gd25Co25Al25Y15RE10 (RE = Dy, Ho, and Er) high entropy metallic glasses were fabricated.•With the substitution of Y by Dy, Ho, or Er, the glassy forming ability, thermal stability, and magnetocaloric properties are improved.•The magnetic transition temperature of these alloys has no obvious correlation with the changing trend of de Gennes factor.•Gd25Co25Al25Y15Ho10 with the excellent refrigeration capacity can be as an attractive candidate for magnetic refrigerants.