Hyperfine Magnetic Fields at the Nuclei of ⁵⁷Fe in the Intermetallic System Zr_{1 –x}Sc_xFe₂

Abstract

Mössbauer studies of the anisotropy of hyperfine interactions (HFIs) of the ⁵⁷Fe nuclei in the quasi-binary intermetallic system Zr_{1 –x}Sc_xFe₂ (0 ≤ x ≤ 1) with the structure of the cubic Laves phase of the C15 type have been performed. Within the framework of the tensor description of the anisotropy of magnetic HFIs, taking the crystal and magnetic structure into account, the hyperfine parameters of the partial spectra have been expressed through the constant of the quadrupole interaction, the isotropic and anisotropic magnetic fields, and also the azimuthal and polar angles, which specify the orientation of the direction of the easy axis of magnetization (EA). It has been established that at temperatures of 87 and 297 K the EA deviates in the plane $(1\bar {1}0)$ from the crystallographic direction [111] by ~15°, and with an increase in the concentration x, the orientation of the EA almost does not change. The changes in the isotropic field and in the shift of the Mössbauer line have an anomalous character. With an increase in x, an increase can first be observed, and then, at x > 0.4, a decrease of the magnitude of the isotropic field can be observed. The shift of the Mössbauer line decreases with an increase in x; at x ~ 0.4, a bent is observed. This anomalous behavior of the isotropic field and of the shift correlates with a change in the lattice parameter and in the magnetic moment of the Fe atoms. The anisotropic field decreases linearly with an increase in the concentration of Sc atoms, while the constant of the quadrupole interaction almost does not change, ~1 mm/s.