Effect of configuration entropy on magnetocaloric effect of rare earth high-entropy alloy

In this work, the relationship between configuration entropy and isothermal magnetic entropy change (Delta S-M) of rare earth high-entropy alloys (HEAs) was studied. The results show that the matrix of rare earth HEAs GdTbHoEr exhibits the largest refrigerant capacity up to now (about 924.48 J kg(-1) at a 5 T magnetic field). With the addition of non-magnetic elements La and Y, the configuration entropy increases, but the values of Delta S-M and the refrigerant capacity decrease from 8.64 to 5.85 J kg(-1)K(-1), 924.48-245.70 J kg(-1), re-spectively. Further, the magnetic element Pr was added to GdTbHoEr, which also increased the configuration entropy and provided magnetism, but the Delta S-M of the HEAs GdTbHoErPr (6.92 J kg(-1)K(-1)) still decreased. The analysis shows that the magnetocaloric effect of HEAs just depend on the intrinsic magnetic characteristics of rare earth elements with 4 f electrons and are independent of configuration entropy. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Rare earth high-entropy alloys show promising magnetocaloric properties, with the addition of non-magnetic elements decreasing the isothermal magnetic entropy change and refrigerant capacity. Meanwhile, the addition of magnetic elements increases configuration entropy and magnetism, but still negatively impacts the magnetic entropy change values.