Probe Mössbauer Spectroscopy of BiNi 0.96 57 Fe 0.04 O 3

This paper presents results of a 57Fe probe Mossbauer spectroscopy study of the BiNi0.9657Fe0.04O3 nickelate. The spectra measured above its TN demonstrate that Fe3+ cations heterovalently substitute for Ni2+ nickel (←Fe3+), being stabilized on four sites of the nickel sublattice in the structure of BiNiO3. Calculations in an ionic model with allowance for monopole and dipole contributions to the electric field gradient indicate that the parameters of electric hyperfine interactions between 57Fe probe atom nuclei reflect the specifics of the local environment of the nickel in the structure of the unsubstituted BiNiO3 nickelate. Below TN, Mossbauer spectra transform into a complex Zeeman structure, which is analyzed in terms of first-order perturbation theory with allowance for electric quadrupole interactions as a small perturbation of the Zeeman levels of the 57Fe hyperfine structure, as well as for specific features of the magnetic ordering of the Ni2+ cations in the nickelate studied.