Effects of crystallization treatment on the structure and magnetic properties of Gd65Fe25Zn10 alloy ribbons for magnetic refrigeration

Abstract The structure and magnetic properties of Gd 65 Fe 25 Zn 10 alloy ribbons prepared by melt-spinning followed by crystallization annealing were investigated. In the as-spun ribbons, there is a small amount of α-Gd nanocrystalline existed in the amorphous matrix. After crystallization treatment, besides the pre-precipitated α-Gd phase, GdFe 2 and GdZn crystalline phases precipitated in turn in the amorphous matrix. The Curie temperature ( T C ) of the fully amorphous matrix is ∼250 K. Owing to α-Gd nanocrystalline precipitated in the amorphous matrix, a second order magnetic transition occurs near 288 K for both the as-spun and the as-annealed Gd 65 Fe 25 Zn 10 ribbons. For a field change of 2 T, the maximum magnetic entropy change (−Δ S M ) max for the as-spun and as-annealed ribbons are 1.56–2.31 and 3.83–4.06 J/(kg·K), while the values of refrigeration capacity (RC FWHM ) are 224.0–387.0 and 149.5–158.0 J/kg, respectively. The as-spun Gd 65 Fe 25 Zn 10 ribbons display relatively low (−Δ S M ) max but the largest RC FWHM value due to the wide (−Δ S M ) versus T curve peak. With negligible thermal/magnetic hysteresis losses, relative large (‒Δ S M ) max and its peak temperature near room temperature, the Gd 65 Fe 25 Zn 10 alloy ribbons can be used as the potential magnetic refrigeration material working at room temperature.