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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]

Magnetic refrigeration (MR) based on the magnetocaloric effect (MCE) has been recognized as an environmentally benign and energy-efficient cooling technology. Exploring suitable magnetocaloric materials is a crucial prerequisite for practical MR applications. We have herein provided a systematic investigation of the crystal structure, microstructure, electronic structure, magnetic phase transition, critical behavior, and MCE of the GdCoC compound featuring excellent cryogenic magnetocaloric performance by means of experimental determination and theoretical calculation. The GdCoC compound is crystallized in a simple layered tetragonal crystal structure with a P 4 2 / mmc space group and undergoes two successive ferromagnetic (FM) transitions along with a low-temperature weak antiferromagnetic (AFM) transition under low magnetic fields. Density functional theory calculations confirms the FM coupling of the Gd and Co intra-sublattice interactions, whereas AFM coupling for their inter-sublattice interaction. The magnetic transitions are merged in to one under high magnetic fields which has been confirmed to be second-order type and its critical behavior can be understood in the framework of tri-critical mean-field model, whereas the low-temperature weak AFM transition is belonging to the first-order type. The excellent magnetocaloric performance of the GdCoC compound was identified by the parameters of magnetic entropy change, adiabatic temperature change, temperature-averaged entropy change, relative cooling power, and refrigerant capacity, which are superior to most of the well-known magnetocaloric materials with similar working temperatures, making it attractive for practical cryogenic MR applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology. Here we report a systematical study on the microstructures, magnetic properties and cryogenic magneto-caloric performances of the Gd20Ho20Tm20Cu20Ni20 amorphous ribbons. It is found that the ribbons reveal a second-order phase transition and are accompanied by a table-shaped magneto-caloric effect. The calculated magnetic-entropy-change maximum |ΔSM|, temperature averaged entropy change (i.e., TEC(10)), and refrigerant capacity reach 13.9 J/kg⋅K, 13.84 J/kg⋅K and 740 J/kg with magnetic field change of 0–7 T, respectively, indicating that the present Gd20Ho20Tm20Cu20Ni20 amorphous ribbons are good candidates for magnetic cooling. [ABSTRACT FROM AUTHOR]

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 magnetocaloric effect has been extensively investigated in various types of magnetic solids to not only develop practical magnetic cooling applications but also deepen the understanding of these materials' underlying inherent properties. Through experimental determination and theoretical calculation, we conducted a systematic investigation of Gd 4 Ga 2 O 9 oxide in terms of its structural, magnetic, and magnetocaloric properties and found it to crystallize in a monoclinic structure belonging to the space group P 2 1 / c and to possess an antiferromagnetic semiconducting ground state. The consistent elements were uniformly distributed up to the nanoscale and presented as Gd3+, Ga3+, and O 2 states, respectively. The magnetocaloric performances of Gd 4 Ga 2 O 9 oxide were checked according to the parameters of maximum magnetic entropy change, refrigerant capacity, and temperature-averaged entropy changes (lift of 5 K), which were determined to be 25.77 J/kgK, 218.27 J/kg, and 23.43 J/kgK under 0–7 T magnetic field change. These parameters of Gd 4 Ga 2 O 9 oxide are comparable to those of some recently reported materials with prominent performances, which means that it can be considered for cryogenic magnetic cooling applications. [ABSTRACT FROM AUTHOR]

We herein provided a systematical determination of the structural and magnetic properties, especially of the magnetocaloric effect (MCE) and magnetocaloric performances of four rare-earth oxychlorides, i. e., the RE OCl (RE = Ho, Dy, Tb and Gd) compounds. The studied RE OCl compounds are all crystallized in the tetragonal matlockite structure (P 4/ nmm space group) and the RE , O, and Cl elements are with the RE 3+, O2−, and Cl− valence states, respectively. The DyOCl, TbOCl and GdOCl compounds reveal an antiferromagnetic transition at around approximate 9.5, 3.7 and 4.8 K, respectively. The magnetocaloric performances are checked by the maximum magnetic entropy change, relative cooling power, and temperature-averaged entropy change with 5 K lift, which are found to be 14.16 J/kgK, 375.55 J/kg and 13.89 J/kgK for HoOCl, to be 14.88 J/kgK, 488.14 J/kg, and 14.60 J/kgK for DyOCl, to be 14.59 J/kgK, 419.67 J/kg, and 14.42 J/kgK for TbOCl, and to be 16.16 J/kgK, 213.68 J/kg, and 14.39 J/kgK for GdOCl, with the magnetic field change of 0–7 T, respectively. [ABSTRACT FROM AUTHOR]

In this work, polycrystalline oxides viz., Ho 2 CrMnO 6 (HCMO) and Er 2 CrMnO 6 (ECMO), were prepared using the sol-gel process, and their crystal structure, magnetic properties, and magnetocaloric effects (MCEs) were studied. X-ray refinement results demonstrate that both oxides exhibited the B -site disordered perovskite type structure (Pbnm space group). A ferromagnetic-paramagnetic phase transition as well as large reversible MCEs was also observed at Curie temperatures (T C) of ~6.1 and ~5.2 K for HCMO and ECMO, respectively. For a magnetic field change (ΔH) of 0–7 T, the maximum magnetic entropy change (-Δ S M), temperature-averaged entropy change (TEC 3), and relative cooling power (RCP) were estimated to be 11.03 J/kgK, 11.02 J/kgK, and 322.7 J/kg for HCMO, and 12.94 J/kgK, 12.80 J/kgK and 277.5 J/kg for ECMO. [ABSTRACT FROM AUTHOR]

• The RE 2 Ga 2 Mg (RE = Tm, Er, Ho) compounds were fabricated. • The magnetic and magnetocaloric properties were investigated. • Large conventional and inverse magnetocaloric effects were observed. • The Tm 2 Ga 2 Mg is considerable for cryogenic magnetic cooling. The Mo 2 FeB 2 -type compounds RE 2 Ga 2 Mg (RE = Tm, Er, Ho) (space group P 4/ mbm) exhibit a large magnetocaloric (MC) effect which makes them promising for use in cryogenic magnetic cooling applications. They exhibit low temperature metamagnetic nature below their Néel temperatures of 6.8, 11.7 and 18.4 K for Tm 2 Ga 2 Mg, Er 2 Ga 2 Mg and Ho 2 Ga 2 Mg, respectively. The magnetic entropy change, the temperature-averaged entropy change (3 K-lift), and the relative cooling power under a magnetic field change of 0–7 T are 15.6, 15.4 J/kgK and 275.8 J/kg for Tm 2 Ga 2 Mg; 13.2, 13.0 J/kgK and 268.0 J/kg for Er 2 Ga 2 Mg; as well as 9.1, 9.0 J/kgK and 223.0 J/kg for Ho 2 Ga 2 Mg, respectively. [ABSTRACT FROM AUTHOR]