Аннотация:The electrical hyperfine interactions of the 57Fe probe nuclei stabilized in the structure of theBiMn7O12 manganite are studied by Mössbauer spectroscopy. Mössbauer spectra are measured in the paraelectric temperature range, which includes the structural phase transitions I2/m ↔ Im (T1 ≈ 600 K) and Im ↔ I2/m (T2 ≈ 450 K). The calculation of the parameters of the electric field gradient tensor with allowance for the dipole contributions of Bi3+ cations in the range of the first phase transition allowed us to confirm a random orientation of the dipole moments pBi in the cubic phase of the manganite (Im ). Based on an analysis of the Mössbauer spectra recorded at T2 < T < T1, we considered various scenarios for the manifes-tation of the dynamic Jahn–Teller effect, which leads to the “melting” of the orbital order in the manganese sublattice, in terms of a two-level relaxation model.
