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Monodisperse FeCo nanoparticles were synthesized via thermal decomposition of appropriate organometallic complexes in heated toluene containing surfactants, aiming to a soft magnetic nanomaterial with a high metal percent. The particles were characterized by X-ray powder diffraction, electron microscopy, and static magnetometry techniques. The effect of air exposure on the structural and magnetic properties was examined. Portions of the dried nanoparticles were mixed with additional surfactants or polyvinylpyrrolidone, followed by redispersion into tetrahydrofuran, so as to study arrangement features in the first case, while the use of polyvinylpyrrolidone intended to the expansion of the interparticle distances in order to get more "isolated" nanoparticles.

The electronic and magnetic structures of a hydrogenated and hydrogen free superlattice of three iron monolayers and nine vanadium monolayers are studied using the first principle full-potential augmented-plane-wave method as implemented in WIEN2k package. The average and the local magnetic moments of the system are studied versus the hydrogen positions at the octahedral sites within the superlattice and also versus the filling of the vanadium octahedral location by hydrogen atoms. The local Fe magnetic moment and the average magnetic moment per iron atom are found to increase as the H position moves towards the Fe–V interface. On the other hand, the average magnetic moment per Fe atom is found to initially decrease up to filling by three H atoms and then increases afterwards. To our knowledge, this is the first reporting on the increase in the computed magnetic moment with hydrogenation. These trends of magnetic moments are attributed to the volume changes resulting from hydrogenation and not to electronic hydrogen–metal interaction.

An effective-substrate method was presented to obtain the optical constants of an iron native oxide layer with unknown optical constants and film thickness on an iron substrate with unknown optical constants by using spectroscopic ellipsometry (SE). "Thick" iron films were deposited on silicon wafer by magnetron sputtering and were exposed to air at room temperature. They were measured by spectroscopic ellipsometry during this procedure at different time points from ten minutes to seven months. Pseudo optical constants were calculated from the initially measured data and were introduced into the modeling work of subsequent measurements as an effective substrate in order to obtain the optical constants and film thickness of the native oxide layer. After obtaining the optical constants of the subsequent native oxide layer, they were employed in the modeling work of the initially measured data and the optical constants of the iron substrate and the film thickness of the initial native oxide layer was obtained.

The structure and processes of mass, charge and heat transfer are investigated in an equiatomic Fe–Ni composite fabricated by electroconsolidation using the spark plasma sintering (SPS) technology. The system contains regions of almost pure Fe and Ni, separated by areas with variable concentration of components, formed in consequence of the interdiffusion in the electroconsolidation process. The interdiffusion coefficient of the Fe–Ni system has been revealed to be significantly higher than that of an alloy of a similar composition at the same temperature, which is likely the result of the employed SPS technology and the enhanced diffusion along the grain boundaries. The concentration dependence of the interdiffusion coefficient passes through a maximum at a Ni concentration of $\sim$70 at.%. The electrical and thermal conductivity of the studied system is significantly higher than that of an alloy of the same composition. The temperature dependence of the resistivity of the sample in the range 5–300 K is due to the scattering of electrons by defects and phonons, and the scattering of electrons by phonons fits well to the Bloch–Grüneisen–Wilson relation. The boundaries of the conductivity of the investigated composite correspond to the Hashin–Shtrikman boundaries for a three-phase system, if Fe, Ni and the FeNi alloy are selected as phases.

Earth’s core consists of a solid inner core and a liquid outer core, composed primarily of iron. The pressure in the solid inner core is about 330 gigapascals (GPa) at the temperature close to the melting point. Considering the extensive experimental and theoretical data, the shear wave ($s$-wave) velocity of the inner core is much lower than that of pure iron. Since the lower $s$-wave velocity has been observed in the seismic models, reasons have been widely discussed such as the premelting of iron in the Earth’s inner core. In this paper, a new explanation is expected to be proposed under the anisotropic stress. The calculated longitudinal wave and $s$-wave velocity of pure hexagonal close-packed iron (HCP-Fe) model based on the density functional theory (DFT) at the different density are matching with the seismic wave, the atomic distribution of HCP-Fe is obtained under the anisotropic stress. Unfortunately, it is unlikely conformed there was an inner-core condition due to the unreal anisotropic stress, although the lower $s$-wave velocity is. Somehow, this lower $s$-wave velocity may provide a new horizon to build mineralogical models for discussing. In addition, the $s$-wave and viscosity of iron are strongly dependent on shear stress, we then give a mathematical equation between the $s$-wave velocity and viscosity empirically by the shear behavior. It is revealed that the shear stress of iron has a positive influence on the $s$-wave and viscosity.