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Abstract It is well known that rare earth (RE) based intermetallic compounds reveal various interesting magnetic properties depending on the crystallized structures and the constituent elements, paving the way for potential applications in different fields. Recent progresses regarding magnetic properties and magnetocaloric effect (MCE) in ternary rare earth RE 2 T 2 X (RE = Gd-Tm; T = Cu, Ni, Co; and X = Cd, In, Ga, Sn, Al) intermetallic compounds are reviewed in this paper. Some of them exhibit excellent MCE performances which make them attractive in the field of magnetic refrigeration at low temperature. With the aim of understanding the magnetocaloric characteristics of RE 2 T 2 X compounds, the crystal structure, magnetism and magnetic phase transition are also focused. The origin of the MCE together with the physics behind and the potential application of RE 2 T 2 X compounds are thoroughly considered. Highlights • Magnetic and magnetocaloric properties in RE 2 T2X compounds are reviewed. • The RE 2 T2X compounds show four types of crystallize structures. • Some of them exhibit excellent cryogenic magnetocaloric performances. • The origin of magnetocaloric effect in RE 2 T2X compounds is discussed. [ABSTRACT FROM AUTHOR]

The rare-earths (RE) based amorphous materials with large magnetocaloric (MC) effects and excellent glass forming ability (GFA) have been recognized as promising candidates for magnetic refrigeration (MR). In this work, the RE 60 Co 20 Al 20 (RE = Ho, Er, Tm) amorphous ribbons were successfully fabricated and systematically determined with respect to the GFA, magnetic properties and MC effects. A second order magnetic phase transition (MPT) from ferromagnetic to paramagnetic (FM to PM) without noticeable field or thermal hysteresis has been observed around the Curie temperatures, T C ~ 22.3 K for Ho 60 Co 20 Al 20 , ~ 10.3 K for Er 60 Co 20 Al 20 , and ~ 5.0 K for Tm 60 Co 20 Al 20 , respectively. The MC parameters including the maximum magnetic entropy change (| Δ S M max |), temperature-averaged entropy change with 3 K lift [ TEC (3 K)], and relative cooling powder/refrigerant capacity (RCP/RC) have been determined to check the MC performances, and the corresponding values are determined to be 14.16, 15.57 and 15.06 J/kgK, to be14.04, 15.38 and 14.78 J/kgK, and to be 625.0/478.7, 505.7/391.8 and 334.0/243.4 J/kg for Ho 60 Co 20 Al 20 , Er 60 Co 20 Al 20 and Tm 60 Co 20 Al 20 under the field change Δμ 0 H = 5 T, respectively. The present results indicate that RE 60 Co 20 Al 20 (RE = Ho, Er, Tm) amorphous ribbons are considerable for cryogenic MR application. • The RE 60 Co 20 Al 20 (RE = Ho, Er, Tm) amorphous ribbons are fabricated. • The glass forming ability in RE 60 Co 20 Al 20 amorphous ribbons was investigated. • Large magnetocaloric effect in RE 60 Co 20 Al 20 has been observed. • RE 60 Co 20 Al 20 ribbons are considerable for cryogenic magnetic refrigeration. [ABSTRACT FROM AUTHOR]

The crystal structure together with the magnetic and magnetocaloric properties in RE 2 Ni 1.5 Ga 2.5 (RE = Dy, Ho, Er and Tm) have been investigated systematically. All the RE 2 Ni 1.5 Ga 2.5 compounds crystallize in a CaIn 2 -type structure of (P63/mmc space group). A second-ordered magnetic phase transition (SOPT) from ferromagnetic to paramagnetic (FM to PM) is occurred in RE 2 Ni 1.5 Ga 2.5 compounds with the Curie temperatures (T C) of approximately 16.1, 10.6, 4.1 and below 2 K for RE of Dy, Ho, Er and Tm, respectively. The magnetocaloric parameters including magnetic isothermal entropy change/temperature-averaged magnetic entropy change -Δ S M max/ TEC (5) and relative cooling power RCP are calculated with the values of 10.01/9.92 J/kg K and 418.6 J/kg for Dy 2 Ni 1.5 Ga 2.5 , 20.12/19.65 J/kg K and 644.1 J/kg for Ho 2 Ni 1.5 Ga 2.5 , 18.07/17.69 J/kg K and 447.1 J/kg for Er 2 Ni 1.5 Ga 2.5 , as well as 18.22/16.75 J/kg K and 330.7 J/kg for Tm 2 Ni 1.5 Ga 2.5 with magnetic field change (Δ H) of 0–7 T, respectively. Notably, Ho 2 Ni 1.5 Ga 2.5 exhibits ralatively high magnetocaloric parameters, which suggests that Ho 2 Ni 1.5 Ga 2.5 is a competitive candidate among the MCE materials in the field of cryogenic magnetic refrigeration (MR). • Magnetic properties and MCE in RE 2 Ni 1.5 Ga 2.5 compounds were studied. • Large values of -ΔS M max, TEC and RCP were observed at low temperature. • Ho 2 Ni 1.5 Ga 2.5 compound is competitive for cryogenic magnetic cooling. [ABSTRACT FROM AUTHOR]

The magnetic refrigeration (MR) by utilizing the magnetocaloric effect (MCE) of magnetic solids has been considered a promising, environmentally benign, energy-efficient cooling technology. However, the lack of promising magnetic substances has slowed the development of its active application. To identify suitable candidate materials, we herein identified the structural and magnetic properties together with the MCE and magnetocaloric performances of rare earth (RE) rich RE 6 Ni 2.25 Al 0.75 (RE = Dy, Ho and Er) compounds. All the RE 6 Ni 2.25 Al 0.75 compounds are confirmed to crystallized in orthogonal Ho 6 Co 2 Ga-type structure and underwent paramagnetic to antiferromagnetic magnetic transitions. Moreover, large direct (conventional) and inverse MCEs have been observed in all the RE 6 Ni 2.25 Al 0.75 compounds. The values of peak magnetic entropy changes, temperature-averaged magnetic entropy changes with 5 K-lift and relative cooling powers under magnetic field change of 0–7 T are evaluated to be − 4.44 J/kg-K, − 4.38 J/kg-K and 230.6 J/kg for Dy 6 Ni 2.25 Al 0.75 , to be − 12.68 J/kg-K, − 12.26 J/kg-K and 378.2 J/kg for Ho 6 Ni 2.25 Al 0.75 , and to be − 17.52 J/kg-K, − 17.33 J/kg-K and 465.7 J/kg for Er 6 Ni 2.25 Al 0.75 , respectively. • The RE6Ni2.25Al0.75 (RE = Dy, Ho and Er) compounds are fabricated. • The structural and magnetic properties were investigated. • Large direct and inverse magnetocaloric effects were observed. • The Er6Ni2.25Al0.75 is considerable for cryogenic magnetic refrigeration. [ABSTRACT FROM AUTHOR]