Enhanced magnetocaloric performance in nanocrystalline/amorphous Gd3Ni/Gd65Ni35 composite microwires

Abstract

A novel class of nanocrystalline/amorphous Gd 3 Ni/Gd 65 Ni 35 composite microwires were created directly from melt-extraction through controlled solidification. X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) confirmed the formation of a biphase nanocrystalline/amorphous structure in these wires. Magnetic and magnetocaloric experiments indicate a large magnetic entropy change (-Δ S M ~9.64 J/kg K), large refrigerant capacity ( RC ~742.1 J/kg), and large maximum adiabatic temperature change ( Δ T a d max ~5 K) around the Curie temperature of ~120 K for a field change of 5 T. These values are ~1.5 times larger relative to its bulk counterpart and are superior to other candidate materials being considered for active magnetic refrigeration in the liquid nitrogen temperature range. • Novel nanocrystalline/amorphous Gd 3 Ni/Gd 65 Ni 35 microwires. • Large magnetic entropy change and refrigerant capacity. • Magnetic refrigerators for nitrogen liquefaction.