New DyHoCo medium entropy amorphous microwires of large magnetic entropy change.

We report upon the excellent magnetocaloric effect in melt-extracted DyHoCo medium entropy microwires. The magnetic entropy change (-Δ S M) reaches a large value of ∼11.2 J kg−1 K−1 for a field change (μ 0 Δ H) of 5 T. The large value of -Δ S M is resulted from the large magnetic moments of Dy and Ho. In addition, the DyHoCo microwires show a good cooling efficiency; RC1, RC2 and RC3 are evaluated to be ∼530 J kg−1, ∼417 J kg−1 and ∼279 J kg−1, respectively, at μ 0 Δ H = 5 T. The DyHoCo microwires undergo a second-order paramagnetic-ferromagnetic transition at the Curie temperature of ∼35 K. The excellent magnetocaloric property makes the melt-extracted DyHoCo microwires a promising refrigerant for cryogenic cooling application. Image 1 • Dy 33.3 Ho 33.3 Co 33.4 medium entropy microwires were fabricated by melt-extraction. • DyHoCo microwires possess an amorphous structure and SOMT. • DyHoCo microwires show the excellent MCE performance. [ABSTRACT FROM AUTHOR]