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Mn-based intermetallic compounds have attracted much attention as interesting electronic and magnetic materials exhibiting second-order magnetic phase transitions near room temperature, and as well as these materials can be considered a good model system for inspecting the fundamental aspects of the nature of complex magnetism and the issues related to the magnetocaloric effect. The main interest in this study is to explore how minor impurities of non-transition sp-elements with different atomic radii and valency can affect the structure and electronic properties of the SnMn 2 compound. Here, we discuss the fabrication, crystalline structure, electrical, magnetic, and magnetocaloric properties of some SnMn 2 -based intermetallic phases partially substituted with Ga, In, and Bi. The obtained results reveal that almost all Mn atoms in these compounds exist in the high-spin state with S = 3/2 and only a few fraction of the low-spin Mn. The studied materials demonstrate high electrical resistivity and the Ioffe-Regel condition near room temperature. The magnetic and magnetocaloric properties of the phases are discussed in the context of the effects associated with competing exchange interactions and magnetic frustrations between localized spins. [ABSTRACT FROM AUTHOR]

Magnetic phase transitions and structure anomalies in solid solutions of double manganites Nd1-xPrxBaMn2O6 obtained for the first time have been investigated by magnetometry and X-ray powder diffraction. It has been shown that the structural anomaly in the form of unit cell volume jump and drastic increase of unit cell parameters ratio а/с is not related to the magnetic or metal-insulator phase transitions. [ABSTRACT FROM AUTHOR]

We report results of magnetic studies of glass-forming alloys with nominal composition of AlGdTM (where TM = Cu, Ni, Co, Fe, Mn, Cr, Ti, Zr, Mo, Ta) synthesized by arc-melting. X-ray diffraction analysis and vibrating sample magnetometry were applied to characterize the prepared samples. All the alloys exhibit antiferromagnetic ordering at low temperatures. In some compositions, we observed metamagnetic transitions in external magnetic fields up to 3 T. Analysis of the paramagnetic susceptibility of the considered Al-Gd-TM systems has revealed non-magnetic behavior of the transition metals. We found that the magnetic properties of the studied samples can be described satisfactorily using only the Gd trivalent ions. But in some cases the magnetic moments of gadolinium are slightly larger than the theoretical values, probably, because of an additional contribution of the 5 d electrons. The obtained results are discussed in framework of the assumptions of the strong s- p- d hybridization and frustrated magnetic states of gadolinium. We argue that the hybridization might be one of the main factors improving the glass-forming ability in these ternary alloys. [ABSTRACT FROM AUTHOR]

Manganites of rare earth elements are currently promising materials for electronics, catalysis, current sources and other applications. Their widespread demand is caused by a variety of structural and magnetic effects connected with substitutions in the sublattices of rare earth element and manganese. Substitutions of rare earth element by Sr, Ca, or Ba in manganites are known to impact the Jahn-Teller (JT) transition temperature as well as the concentration of Mn3+ and Mn4+ ions, which influences the efficiency of double exchange in magnetic orderings. In this work, solid solution Sm1-xSrxMnO3 with low concentrations of the substituting element x = 0; 0.15; 0.25 has been studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal analysis, and magnetometry. Samarium manganites have a perovskite-like orthorhombic structure (Pbnm space group). It has been shown that the Sm-by-Sr substitution leads to a gradual increase in the valence of manganese from 3 + to intermediate value 3.67+. This is accompanied by an increase Néel temperature in (TN) from 56 K at x = 0 to 90 K at x = 0.25, in the paramagnetic Curie temperature (Θ) from − 30.3 K at x = 0 to 119.9 K at x = 0.25, as well as in the value of the saturation magnetic moment (µS) from 0.27 µB at x = 0 to 3.49 µB at x = 0.25. In addition, such substitution leads to a decrease in the temperature of the JT structural transition from 996 ºC at x = 0.0 to 252 ºC at x = 0.25. The relationship between the magnetic properties and the crystal structure of samarium manganites is discussed. [ABSTRACT FROM AUTHOR]

This study aims at developing novel Full-Heusler high entropy intermetallic compounds (FH-HEICs). To this end, the formation of Heusler-type intermetallic structures and their thermal stability are studied in three systems with (CoFeNiCuV) 2 MnAl, Co 2 (FeMnNiCuTi)Al and Co 3 (FeMnNiCu)Al chemical compositions, where one sublattice composed of multi-component elements. The results indicated that (CoFeNiCuV) 2 MnAl crystallizes in a pure FH-HEIC type phase consisting of ordered L2 1 and disordered A2 structures, and it remains stable after 5 h annealing at 900 °C. Annealing could effectively suppress segregation of elements in (CoFeNiCuV) 2 MnAl, but it did not trigger substantial disorder-to-order phase transition. Co 2 (FeMnNiCuTi)Al crystallized in a mixture of B2 and FCC phases, in which the ordered B2 structure undergoes a transition to disordered A2 type structure upon annealing at 900 °C. On the other hand, Co 3 (FeNiMnCu)Al exhibited a A2+FCC two-phase structure in both as-cast and annealed states. (CoFeNiCuV) 2 MnAl exhibited higher microhardness value (589 HV) compared to Co 2 (FeMnNiCuTi)Al (474 HV) and Co 3 (FeMnNiCu)Al (417 HV) FH-HEICs, consisting with its higher degree of ordering. Finally, all the samples exhibited ferromagnetic behavior with relatively high magnetic saturation and coercivity in the range of semi hard magnetic materials. [Display omitted] • Full-Heusler high entropy intermetallic compounds (FH-HEICs) are developed. • (CoFeNiCuV) 2 MnAl FH-HEICs composed of ordered L2 1 and disordered A2 structures. • The microhardness of FH-HEICs are correlated with the degree of ordering in lattice structure. • FH-HEICs exhibited ferromagnetic behavior with relatively high magnetic saturation. • Entropy engineering is an effective route to improve functional properties of Heusler phases. [ABSTRACT FROM AUTHOR]