Magnetic properties and large magnetocaloric effect in the amorphous RE2Co (RE = Tb, Dy, Er) ribbons

The microstructure, phase transition and magnetocaloric properties of RE₂Co (RE = Tb, Dy, Er) prepared by melt-spinning technology were studied. XRD and DSC confirmed the formation of RE₂Co (RE = Tb, Dy, Er) ribbons with amorphous nature. The DSC analysis results show that the first crystallization temperature of RE₂Co (RE = Tb, Dy, Er) amorphous alloys are 565 K, 590 K, and 644 K, respectively, while their melting temperatures are 972 K, 998 K, and 1066 K, indicating excellent thermal stability of the ribbon alloys. The RE₂Co (RE = Tb, Dy, Er) ribbons exhibit second-order ferromagnetic–paramagnetic transition at Curie temperatures of 92 K, 47 K, and 11 K, respectively. The RE₂Co (RE = Tb, Dy, Er) ribbons exhibit paramagnetic behavior consistent with Curie-Weiss law in the paramagnetic region, with paramagnetic Curie temperatures of 98 K, 54 K, and 3 K, respectively, where positive θ_p denotes the dominance of ferromagnetic contribution. For a magnetic field change of 0–5 T, the maximum magnetic entropy changes of RE₂Co (RE = Tb, Dy,) are 8.9 J/kg K and 7.8 J/kg K, respectively, with the corresponding refrigerant capacity values of 446.1 J/kg and 361.5 J/kg, while the maximum magnetic entropy change for Er₂Co is more than 27.1 J/kg K. The notable magnetocaloric effects indicate that the amorphous alloys RE₂Co (RE = Tb, Dy, Er) present promising potential as viable candidates for magnetic refrigeration applications at lower temperatures.