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Rare-earth based amorphous alloys with promising glass forming ability (GFA) and considerable magnetocaloric effect (MCE) are extensively exploited for magnetic refrigeration (MR) materials. Here, the GFA, magnetic properties, MCE, and refrigeration performance of RE60Al20Ni20 (RE = Tm, Er, and Ho) amorphous ribbons were investigated. A magnetic phase transition (paramagnetic to ferromagnetic, second-order) with ignorable field and thermal hysteresis was found around TC ∼ 4.4 K for Tm60Al20Ni20, ∼9.5 K for Er60Al20Ni20, and ∼17.9 K for Ho60Al20Ni20. For a field change ΔH = 50 kOe, the MCE parameters of the maximal magnetic entropy change (around their own TC) and relative cooling power are 14.1 J/kg K and 235 J/kg for Tm60Al20Ni20, 14.3 J/kg K and 372 J/kg for Er60Al20Ni20, and 12.4 J/kg K and 460 J/kg for Ho60Al20Ni20. In addition, the temperature averaged entropy change at ΔTlift (temperature span) of 2 K and 5 K is investigated, very close values and similar field dependence with magnetic entropy change indicating that RE60Al20Ni20 (RE = Tm, Er, and Ho) has potential applications in cryogenic magnetic refrigeration. [ABSTRACT FROM AUTHOR]

The intermetallic gallium compounds RE2Co2Ga with different rare earths (RE = Dy, Ho, Er, and Tm) were synthesized, and their crystal structure, microstructure, magnetic, and cryogenic magneto-caloric performances were investigated. The RE2Co2Ga compounds crystallize with an ordered orthorhombic W2B2Co-type structure (space group Immm). All the RE2Co2Ga compounds undergo ferromagnetic (FM) ordering (second-order) from a paramagnetic to FM transition which induces reversible magneto-caloric effects (MCE). The Curie temperatures (TC) in RE2Co2Ga compounds are determined to be 55.0, 38.5, 25.5, and 11.6 K for RE = Dy, Ho, Er, and Tm, respectively, which fulfill the de Gennes scaling. The RE2Co2Ga compounds show relatively small MCE (i.e., −ΔSM, isothermal magnetic entropy change) around their own phase transition temperatures, and the maximal values of −ΔSM are 7.5, 14.6, 11.2, and 13.2 J/kg K in the field change (ΔH) of 7 T for RE = Dy, Ho, Er, and Tm, respectively. Accordingly, the values of the relative cooling power are 212, 335, 304, and 239 J/kg, respectively. [ABSTRACT FROM AUTHOR]