Amorphous and crystallized (Gd4Co3)100―xBx alloys for magnetic refrigerants working in the vicinity of 200 K

• Published in: Journal of alloys and compounds 2013-03, Vol.553, p.152-156
• Main Authors: ZHONG, X. C, GAO, B. B, LIU, Z. W, ZHENG, Z. G, ZENG, D. C
• Format: Article
• Language: English
• Subjects: Alloys; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystallization; Entropy; Exact sciences and technology; Magnetic properties; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect, magnetic cooling; Metallic glasses; Physics; Refrigerants; Reinforced concrete; Ribbons
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.11.086

Crystallized Gd4Co3 alloy has shown promising magnetocaloric properties resulting from two successive magnetic-entropy changes of the hexagonal phase. In this work, magnetic (Gd4Co3)100-xBx (x = 0, 5, 10 and 15) amorphous ribbons were prepared by melt spinning. The onset crystallization temperatures Tx for the alloys with x = 0, 5, 10 and 15 were found to be about 560, 565, 575 and 585 K, respectively. The Ho4Co3-type hexagonal phase was obtained for crystallized ribbons after annealing. All the amorphous and crystalline alloys order ferromagnetically and undergo the second-order transition at their Curie temperatures. Under an applied field change from 0 to 5 T, the maximum value of (-ISM) for (Gd4Co3)100-xBx amorphous alloys increased from 6.7 to 7.8 J kg-1 K-1 with increasing B content. Large values of the refrigerant capacity (RC) were also obtained. For the crystallized alloys, the maximum value of (-ISM) decreased to 6.2a6.4 J kg-1 K-1. Large magnetic entropy change and RC value, negligible coercive force and hysteresis, as well as high stability enable the (Gd4Co3)100-xBx amorphous alloys competitive candidates for the magnetic refrigeration materials working in the vicinity of 200 K.