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

The structure and magnetic properties of Gd65Fe25Zn10 alloy ribbons prepared by melt-spinning followed by crystallization annealing were investigated. In the as-spun ribbons, there is a small amount of alpha-Gd nanocrystalline existed in the amorphous matrix. After crystallization treatment, besides the pre-precipitated alpha-Gd phase, GdFe2 and GdZn crystalline phases precipitated in turn in the amorphous matrix. The Curie temperature (T-C) of the fully amorphous matrix is similar to 250 K. Owing to alpha-Gd nano-crystalline precipitated in the amorphous matrix, a second order magnetic transition occurs near 288 K for both the as-spun and the as-annealed Gd65Fe25Zn10 ribbons. For a field change of 2 T, the maximum magnetic entropy change (similar to Delta 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 (RCFWHM) are 224.0-387.0 and 149.5-158.0 J/kg, respectively. The as-spun Gd65Fe25Zn10 ribbons display relatively low (similar to Delta S-M)(max) but the largest RCFWHM value due to the wide (similar to Delta S-M) versus T curve peak. With negligible thermal/magnetic hysteresis losses, relative large (similar to Delta S-M)(max) and its peak temperature near room temperature, the Gd65Fe25Zn10 alloy ribbons can be used as the potential magnetic refrigeration material working at room temperature. (C) 2017 Elsevier B.V. All rights reserved.