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• 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]

• The optimum ball-milling time is 3–5 h to obtain amorphous alloy. • The theory of the energy barrier and schematic diagram of atomic arrangement were adopted to interpret the amorphization and crystallization mechanisms. • The uniform microstructure was obtained by annealed at 700 ℃ for 20 min. • The coercivity (H cj) and the remanence (B r) are increased by 1.28 kOe and 23.6 emu/g, respectively. The phase transformation mechanism and magnetic properties of the Sm-Fe alloy powders produced by melt-spinning and high-energy ball milling are investigated. The amorphous phase is stable between 2 and 5 h, and the SmFe 9 phase is precipitated from the amorphous matrix after milled for 5 h. The time of 3–5 h is optimal to obtain the largest number of short-range/medium-range order in the amorphous alloy, which can contribute to the formation of uniform microstructure in the subsequent crystallization annealing process. The magnetic properties of the nitrided powders produced by crystallizing the amorphous precursors are improved compared to the properties of those produced by direct melt-spinning. The coercivity (H cj) and the remanence (B r) are increased by 1.28 kOe and 23.6 emu/g, respectively. This kind of micro-regulation plays a key role in improving the magnetic properties after nitrogenating and lays the foundation for the production of bulk materials in the future. [ABSTRACT FROM AUTHOR]

• The magnetism and magnetocaloric effect (MCE) were investigated in Er 4 CoCd compound. • A large magnetocaloric effect in Er 4 CoCd compound was observed. • The origin of MCE and its potential application in Er 4 CoCd were discussed. The Er-based compound Er 4 CoCd was synthesized successfully and its structural, magnetic together with magnetocaloric properties were investigated in detail. The Er 4 CoCd crystallized in a Gd 4 RhIn-type structure with the space group of F 4 ¯ 3 m , which was confirmed by Rietveld refinement. A ferromagnetic transition was observed around its Curie temperature (T C) of 12.5 K accompanied by a large magnetocaloric effect (MCE). The performance of MCE for Er 4 CoCd was evaluated by the isothermal maximal magnetic entropy (- Δ S M max) , the temperature averaged entropy change (TEC) at 10 K temperature lift [ TEC (10 K)], and the relative cooling power (RCP). The values of - Δ S M max , TEC (10 K), and RCP of Er 4 CoCd are 20.4 J/kg K, 19.2 J/kg K, and 503 J/kg under the magnetic field change (Δ H) of 0–5 T, respectively. [ABSTRACT FROM AUTHOR]