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The structural and magnetic behavior of Mn-site doped intermetallic manganese silicide alloys of nominal compositions Mn5−xAxSi3 (x = 0.05, 0.1, 0.2 and A = Ni, Cr) have been investigated with a focus to the inverted hysteresis behavior and thermomagnetic irreversibility. Room temperature x-ray powder diffraction data confirm that all the doped alloys crystallize in hexagonal D88 type structure with space group P 63/mcm. The doped alloys are found to show paramagnetic (PM) -collinear antiferromagnetic (AFM2) -noncollinear antiferromagnetic (AFM1) transitions during cooling from room temperature. A significant decrease in the critical values of both AFM1-AFM2 transition temperatures and fields have been observed with the increasing Ni/Cr concentration. Inverted hysteresis loop, field-induced arrest, and thermomagnetic arrest, the key features of the undoped Mn5Si3 alloy, are found to be significantly affected by the Mn-site doping and eventually vanishes with 4% doping.

Ternary carbide in metal matrix composites constitute a big challenge in the industry, and in this regard their surface treatment is one of the most important issues. Ternary carbide (CuxTiyCz, where x, y and z are integers) thin films are synthesized by magnetron sputtering and characterized with respect to the film depth. X-ray photoelectron spectroscopy (XPS) of Cu-2p and Ti-2p peaks shows the associated shake-up satellite peaks at a smaller film depth; the peak intensity is reduced at a higher depth. The relative intensity of Cu and Ti increases at a larger film depth. The optical band gap varies from 1.83 to 2.20 eV at different film depths.

The influence of sp-d hybridization on the electronic structure of different Al-Mn alloys has been studied by photoelectron spectroscopy. Experimental evidence of a pseudogap in a crystalline binary Hume-Rothery alloy is provided. The pseudogap varies systematically with Mn concentration. The sp-d hybridization alone, even in the absence of Hume-Rothery mechanism, can produce the pseudogap. Existence of the pseudogap, suppression of the Mn 2p satellite, and decrease in the Doniach-Šunjić asymmetry parameter are the consequences of the sp-d hybridization. An in situ method of preparing these alloys by annealing a Mn adlayer on Al͑111͒ is presented.

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Transport measurements data are presented on bismuth-rich BiFeO3 ceramic, synthesized by a solid state method. Conductivity isotherms were analyzed using Jonscher’s empirical power-law frequency dependence. Monotonically increasing frequency-exponent n(T) over 413–593 K indicates a small polaron tunnelling mechanism for the charge transport. Distinct linear regimes observed in the Arrhenius σdc vs. T−1 plot suggest that two different charge-carriers/conductivity-relaxations prevail above and below ∼490 K. Twin Arrhenius regimes of ac-conductivity also exhibit a sharp “transition” at 510 K, from the pinned-dipole/hopping-anion dynamics to the free-dipole/oscillating-ions response at higher temperatures. Furthermore, a concurrent behavior-change of the locus traced out by the charge-hopping frequency ωh [with σ(ωh) = 2σdc] also designates 510 K as delineating two different transport characteristics in the adjacent temperature regimes.

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