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The synthesis conditions for the gadolinium manganite doped with barium (x = 0.1) are determined. The sequence and typical features of phase formation during the synthesis of Gd0.9Ba0.1MnO3 are determined. It is revealed that the β→γ-BaCO3 phase transformation at T = 960 °C leads to an increase in the reactivity of the initial reagents. At this stage, the Gd0.9Ba0.1MnO3 formation centers begin to grow. Intermediate grinding is necessary to homogenize the phase; additional annealing at T = 1250 °C is applied to stabilize the phase. Substitution of Gd for Ba changes the microstructure of the manganite and leads to suppression of grain growth. Modification of the GdMnO3 manganite with barium leads to partial removal of the Jahn-Teller distortions, and as a consequence to a decrease in temperature of the phase transition O'→O. The addition of barium does not affect noticeably the magnetic behavior of the initial manganite but decreases the magnetic moment and stimulates ferromagnetic correlations in its antiferromagnetic manganese subsystem. [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]

The synthesis conditions for the gadolinium manganite doped with barium (x = 0.1) are determined. The sequence and typical features of phase formation during the synthesis of Gd0.9Ba0.1MnO3 are determined. It is revealed that the β→γ-BaCO3 phase transformation at T = 960 °C leads to an increase in the reactivity of the initial reagents. At this stage, the Gd0.9Ba0.1MnO3 formation centers begin to grow. Intermediate grinding is necessary to homogenize the phase; additional annealing at T = 1250 °C is applied to stabilize the phase. Substitution of Gd for Ba changes the microstructure of the manganite and leads to suppression of grain growth. Modification of the GdMnO3 manganite with barium leads to partial removal of the Jahn-Teller distortions, and as a consequence to a decrease in temperature of the phase transition O'→O. The addition of barium does not affect noticeably the magnetic behavior of the initial manganite but decreases the magnetic moment and stimulates ferromagnetic correlations in its antiferromagnetic manganese subsystem. [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]