Magnetic properties and magnetocaloric effect of GdTbHoEr-based high-entropy alloy ribbons

In this work, the structure, magnetic properties, and magnetocaloric effect (MCE) of GdTbHoEr-based high-entropy alloy (HEA) ribbons were studied. All samples form single-phase HCP disordered solid solutions and show large MCE, with the magnetic entropy change (Delta S-M) of 7.43, 6.83, and 6.38 J kg(-1) K-1, and the refrigeration capacity values of 838.25, 508.22, and 760.58 J kg(-1), respectively. With the addition of La and Y elements, MCE decreases, but the peak width of the Delta S-M curves increases and gradually presents a "table-like" shape. This decrease in MCE is not due to the dilution of magnetic atoms. The analysis shows that the high chemical disorder and the stability of high configuration entropy make the magnetic transition sluggishly and result in this MCE type. In addition to the excellent MCE, GdTbHoEr-based HEA ribbons have a small hysteresis value, which greatly meets the requirements of magnetic refrigeration technology.