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Moessbauer transmission spectra for the 14.41-keV resonant line in 57Fe have been collected at room temperature by using 57Co(Rh) commercial source and alpha-Fe strain-free single crystal as an absorber. The absorber was magnetized to saturation in the absorber plane perpendicular to the gamma-ray beam axis applying small external magnetic field. Spectra were collected for various orientations of the magnetizing field, the latter lying close to the [110] crystal plane. A positive electric quadrupole coupling constant was found practically independent on the field orientation. One obtains the following value Vzz=+1.61(4)x10^19 V/m^2 for the (average) principal component of the electric field gradient (EFG) tensor under assumption that the EFG tensor is axially symmetric and the principal axis is aligned with the magnetic hyperfine field acting on the 57Fe nucleus. The nuclear spectroscopic electric quadrupole moment for the first excited state of the 57Fe nucleus was adopted as +0.17 b. Similar measurement was performed at room temperature using as-rolled polycrystalline alpha-Fe foil of high purity in the zero external field. Corresponding value for the principal component of the EFG was found as Vzz=+1.92(4)x10^19 V/m^2. Hence, it seems that the origin of the EFG is primarily due to the local (atomic) electronic wave function distortion caused by the spin-orbit interaction between effective electronic spin S and incompletely quenched electronic angular momentum L. It seems as well that the lowest order term proportional to the product L.LAMBDA.S dominates, as no direction dependence of the EFG principal component is seen. The lowest order term is isotropic for a cubic symmetry as one has LAMBDA=lambda.1 for cubic systems with the symbol 1 denoting unit operator and lambda being the coupling parameter.
Molecular dynamics simulations have been performed to understand the influence of temperature on the tensile deformation and fracture behavior of $<$111$>$ BCC Fe nanowires. The simulations have been carried out at different temperatures in the range
The pressure induced bcc to hcp transition in Fe has been investigated via ab-initio electronic structure calculations. It is found by the disordered local moment (DLM) calculations that the temperature induced spin fluctuations result in the decreas
By means of first principles calculations we investigate the nature of exchange coupling in ferromagnetic bcc Fe on a microscopic level. Analyzing the basic electronic structure reveals a drastic difference between the $3d$ orbitals of $E_g$ and $T_{
Crack growth behaviour along the coherent twin boundary (CTB), i.e., $Sigma$3{112} of BCC Fe is investigated using molecular dynamics (MD) simulations. The growth of an atomistically sharp crack with {112}$<$110$>$ orientation has been examined along
We use DFT to compute core structures of $a_0[100](010)$ edge, $a_0[100](011)$ edge, $a_0/2[bar{1}bar{1}1](1bar{1}0)$ edge, and $a_0/2[111](1bar{1}0)$ $71^{circ}$ mixed dislocations in bcc Fe. The calculations use flexible boundary conditions (FBC),