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In this study, zirconium (Zr) successfully substituted for erbium (Er) in Er6–xZrxMnSb2(x = 0, 0.5, 1, 1.5) of the Fe2P type, with comprehensive characterizations on crystal structure, electronic structure and magnetic properties. According to synchrotron powder X-ray diffraction data analysis and density functional theory calculation, Zr does not randomly but preferentially occupy during the doping process and results in weaker magnetic exchange interactions and depressed ordering temperatures. The electronic structure data show that the doping of Zr can weaken interaction between Er and Mn atoms. Owing to multiple transitions, the Er6–xZrxMnSb2(x = 0, 0.5, 1, 1.5) exhibit table-like magnetocaloric effect. Er6MnSb2displays wide δTFWHM(full width at half maximum of the magnetic entropy change curve) of 116 K and high relative cooling power of 388.62 J/kg for 3 T. The maximum magnetic entropy change of Er6–xZrxMnSb2is increased from 3.81 to 7.69 J/(kg·K) with the Zr content up from x = 0 to x = 1.5.

Ternary intermetallic compounds RMn6Ge6with complex magnetic phase transitions are expected to be developed and applied in spintronic storage and computing devices in the future. The relationship between the crystal structure and physical properties (electrical conductivity, thermal analysis, and complex magnetic transformation) of ErMn6–xCoxGe6(x= 0–1.45) alloys was studied in the range of 80–600 K. The result shows that the polycrystalline alloys crystallize in the hexagonal HfFe6Ge6type (P6/mmm). Co doping causes orbital hybridization between Co 2p, Mn 2p, and Er 4d and leads to the presence of mixed valence states of Mn3+and Mn4+, leading to complex magnetic behaviors: the alloys display a Néel point at a high temperature TN(∼500 K), magnetization increases again at TC(∼250 K), and a second peak in the temperature dependence of magnetization at about Tt(∼150 K), which is spin reorientation. We discuss these phenomena in terms of Mn–Mn, Er–Mn, and Mn3+/Mn4+and the prospect for potential applications of the studied alloy in magneto memory and new topological kagome magnet fields.

In this paper, the room-temperature magnet Gd6FeBi2was comprehensively characterized by means of temperature-dependent single-crystal X-ray diffraction, magnetization measurements, and experimental electron density and electronic structure computations. This work explores the electron-spin effects of Fe on this structure and suggests that Gd6FeBi2shows structural features and exchange interactions, which are clearly distinguishable from other analogues, including the solid solutions Dy6–xGdxFeBi2(0 ≤ x≤ 5). The unique traits of Gd6FeBi2and its derivatives encompass abnormal variations of lattice parameters with the temperature, as well as the presence of multiple magnetic transitions of complex nature. Based on the comprehensive analyses, it can be suggested that the unique magnetic response in this material is the result from tunable Fe spin states, which are coupled with strong Gd 5d–Fe 3d interactions, which differ from other members of this large, structural family. In the ground state, according to density functional theory calculations, the Fe atom carries two net electrons, whose spins are coupled in an antiparallel fashion to the spins of the Gd electrons. Near the Curie temperature, the Fe net moment is reduced intermittently, coupled with a multiple of magnetic transitions. The magnetic correlations are manifested in unexpected variations of the lattice parameters as a function of temperature, suggesting spin–lattice interactions. This study emphasizes the important role of Gd 5d electrons in tuning Fe 3d-based magnetic contribution, which enables better understanding on the spin coupling in other related compounds and sheds light on the development of new magnetic and spintronic compounds.

The rare earth (RE)-transition metal (TM) based compounds have emerged as one of the best candidates for the application in eco-friendly and effective cooling technology due to their outstanding cryogenic magnetocaloric performances. In this work, three RE-TM germanides RE3Co2Ge4(RE = Gd, Tb and Dy) were synthesized and characterized, aiming to investigating their structural, magnetic and magnetocaloric properties. These compounds crystallize in the Tb3Co2Ge4-type monoclinic structure (space group C2/m, Z = 2). Two successive ferromagnetic transitions are observed with TCof 31 and 135 K for Gd3Co2Ge4, ferromagnetic and spin reorientation transitions are observed with TCof 24 K and Tsof 19 K for Dy3Co2Ge4, all of which are second ordered. In contrast, Tb3Co2Ge4exhibits a second order antiferromagnetic transition with TNof 36 K, accompanied with a spin reorientation transition with Tsof 17 K. Furthermore, the ferromagnetic ground state for Gd3Co2Ge4is also confirmed by the first-principles calculations. Significant cryogenic magnetocaloric performances are observed in these compounds. The determined maximum magnetic entropy change () under a magnetic field change (ΔH) of 0–7 T are 10.7, 5.3 and 11.6 J/(kg·K) for Gd3Co2Ge4, Tb3Co2Ge4and Dy3Co2Ge4, respectively. Our results suggest that Gd3Co2Ge4and Dy3Co2Ge4compounds are attractive candidates for cryogenic magnetic refrigeration applications.

Rare-earth intermetallic compounds formed in many R-Fe-Mn (R=rare-earth element) systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third element in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems (DyFe2and DyMn2, Dy6Fe23and Dy6Mn23) formed a continuous series of solid solution at 773 K, respectively.