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The rare-earth (RE)-based magnetic solids with large magneto-caloric effect (MCE) have been well investigated recently due to their potential applications in the field of environmentally friendly cryogenic magnetic refrigeration (MR). Herein, two polycrystalline RE-based REFe2Si2 (RE = Dy and Tb) intermetallic compounds have been prepared by an arc-melting way and determined with regard to the structural and magnetic phase transition (MPT) properties as well as the MCE and magneto-caloric performance. Both of the present REFe2Si2 compounds at room temperature are crystallized in a ThCr2Si2-type structure and undergo a first-ordered MPT from antiferromagnetic to paramagnetic state around the Néel temperature (TN) of ~ 4.05 K for DyFe2Si2 and ~ 6.25 K for TbFe2Si2, respectively. Large cryogenic MC effect together with excellent MC performance have been realized in DyFe2Si2 compound. The MC parameters with magnetic field change at 0–5 T of the maximum magnetic entropy changes and the refrigerant capacity/relative cooling power were found to be 16.08 J/kgK and 318.5/403.3 J/kg for DyFe2Si2 and to be 9.88 J/kgK and 105.9/140.8 J/kg for TbFe2Si2, respectively. [ABSTRACT FROM AUTHOR]

Magnetic materials with skyrmionic spin configurations have been widely investigated in recent years owing to their promising applications for magnetic memory storage and logic circuits. Considering their practical applications, room‐temperature skyrmion‐hosting magnetic materials shall be investigated comprehensively. The characteristics of magnetic skyrmions are closely associated with the physical properties of the host magnetic materials. The symmetry of the crystal structure, magnetic order temperature, and geometric shape of magnetic materials significantly affect the formation and annihilation of magnetic skyrmions. In addition to the intrinsic properties of materials, detection methods are vital to the investigation of new materials. Herein, the techniques for detecting magnetic skyrmions are briefly summarized, and the results of room‐temperature magnetic skyrmion hosting magnetic solids (the artificial materials are not included) with different topological characteristics from recent years are presented. [ABSTRACT FROM AUTHOR]

• Three (Mn 0.5 Ni 0.5) 60+ x Ga 40- x skyrmion hosting alloys are fabricated. • Second order magnetic transition was confirmed. • Considerable MCE were observed in rare earth (RE)-free alloys. • Valuable clues for searching RE-free MCE materials. A systematic investigation of rare earth free magnets (Mn 0.5 Ni 0.5) 60+ x Ga 40- x (x = 3.3, 5.0, and 6.6) which are typical skyrmion hosting alloys are presented with respected to the crystal structure, magnetic phase transition and magneto-caloric effect (MCE). All the (Mn 0.5 Ni 0.5) 60+ x Ga 40- x alloys exhibit a hexagonal Ni 2 In-type structure with the P63/mmc space group confirmed by X-ray diffraction. The Mn and Ga/Ni atomic layers arrange alternately along the c -axis. The lattice parameters include a and c all as well as the Curie temperature (T C) all increase gradually with increasing Mn content. A second-ordered phase transitions from the state of ferromagnetic to paramagnetic has been determined around their own T C of 340, 348 and 351 K for (Mn 0.5 Ni 0.5) 63.3 Ga 36.7 , (Mn 0.5 Ni 0.5) 65 Ga 35 and (Mn 0.5 Ni 0.5) 66.6 Ga 33.4 , respectively. Moreover, the MCE performances of (Mn 0.5 Ni 0.5) 60+ x Ga 40- x alloys were determined by the figure merits of the maximum magnetic entropy change (-Δ S M max), temperature-averaged entropy change (TEC) with 5 K-lift and refrigerant capacity (RC). The values of -Δ S M max, TEC (5), and RC are 3.26 J/kg K, 3.24 J/kg K, and 229.9 J/kg for (Mn 0.5 Ni 0.5) 63.3 Ga 36.7 , 3.72 J/kg K, 3.70 J/kg K and 287.3 J/kg for (Mn 0.5 Ni 0.5) 65 Ga 35 , as well as 3.56 J/kg K, 3.53 J/kg K and 265.1 J/kg for (Mn 0.5 Ni 0.5) 66.6 Ga 33.4 under the external applied field change of 0–7 T, respectively. [ABSTRACT FROM AUTHOR]