Abstract

In the last years, the magnetocaloric effect (MCE) of binary Laves phases RT2 (R= rare earth; T= Co, Al, Ni) has been theoretically and experimentally investigated [1,2]; the large magnetic entropy and adiabatic temperature changes found in some of these compounds make them attractive as low temperature magnetic refrigerants (10-80 K). Usually, these materials are produced by conventional melting techniques followed by a long-term thermal annealing [3,4,5,6]. In this contribution, we report the synthesis and magneto-structural characterization of polycrystalline TbAl2 melt-spun ribbons. We studied their microstructure, crystal structure and magnetic properties by SEM, X-ray diffraction (XRD), magnetization measurements. The TbAl2 compound crystallizes into a single phase with the cubic MgCu2-type crystal structure of the Laves phases (C15; space group Fd-3m). From the low-field M(T) curve (5 mT) a Curie temperature TC of 101 K has been measured; such value is similar to the one reported for bulk alloys [7]. The ribbons exhibit an average thickness of 40 µm and are composed by microcrystalline grains. The saturation magnetization at 2 K and 5 T is 206 Am2kg-1. No secondary phases were observed in SEM micrographs, whilst EDS analysis confirmed 1:2 average elemental composition