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A nanostructured NiBi3/α-Bi2O3 superconductor composite has been synthesized by the process of mechanical alloying through 19 h of high energy ball milling. The kinetics of formation is analyzed in detail by x-ray diffraction and the Rietveld method. A simple method is proposed to determine the crystallinity of the resulting sample by using the background Rietveld fitting that permits a quantitative analysis of the diffuse x-ray profile taking into account the air and Compton scattering. The diffuse scattering is attributed to the formation of a nanocluster of α-Bi2O3 which is confirmed by high-resolution transmission electron microscopy and Raman measurements. The magnetic measurements show superconducting transition at around 4 K and the existence of NiBi3/α-Bi2O3 nanophases with a low irreversibility field at around 1.01 T at 2 K. Analysis of magnetic susceptibility and isothermal magnetic hysteresis of the NiBi3/α-Bi2O3 nanocomposite indicates the simultaneous existence of bulk superconductivity and ferromagnetism below 4 K. [ABSTRACT FROM AUTHOR]

A chalcogenide SnS2 – xSex alloy with x = 1, synthesized by high-energy mechanical alloying, was characterized by high-resolution transmission electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and UV-Vis absorbance. The obtained alloy powder was a lamellar solid solution with nanometric crystalline domain sizes and several types of defects such as stacked faults, discordances, crystal fractures, and local atomic disorders. All of these microstructural features lead to the manifestation of different optical and vibrational properties of this extensively deformed nanostructured sample. Raman spectroscopic measurements suggested a two-mode vibration indicating how the S and Se atoms were distributed in the crystalline lattice. The UV-Vis absorbance spectrum showed multiple bandgaps at 1.99, 2.60, 3.09, 3.66, and 4.56 eV that may well be described as direct allowed interband electronic transitions suggesting inhomogeneous strain and domains. [ABSTRACT FROM AUTHOR]