Abstract:
The results of quantum-mechanical calculations of hyperfine interaction parameters (hyperfine fields and isomer shifts at the $^{57}$Fe nucleus) in Fe–Al–B ternary alloys are presented. It is shown that substituting iron atoms with aluminum or boron atoms in the first coordination sphere of the Fe atom leads to a decrease in the hyperfine magnetic field by approximately 2.7 T per atom and an increase in the isomer shift by 0.02 mm/s per atom. The effect of substitutions in more distant coordination shells generally requires further analysis of the local atomic structure. The analysis of contributions to the $^{57}$Fe hyperfine magnetic field from core and valence electrons revealed a proportionality between the hyperfine magnetic field and the magnetic moment of the core d-electrons, with a coefficient of about 12.4 T/$\mu_{\mathrm{B}}$, without a pronounced correlation with the contribution from valence electrons. Energetically stable periodic structures with boron atoms in interstitial positions are considered on the example of the Fe$_{11}$Al$_5\mathbf{B}$ and Fe$_{12}$Al$_4\mathbf{B}$ systems. The obtained results have practical significance for the interpretation of Moessbauer spectra.
Keywords:DFT calculations, Fe–Al–B ternary alloys, hyperfine interactions, local atomic structure.
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