Single-crystal samples of SmFe3 – xScx(BO3)4 (x = 0.17, 0.45) multiferroics have been studied in the temperature range of T = 4–295 K using 57Fe Mössbauer spectroscopy and X-ray diffraction analysis. It has been found that the quadrupole hyperfine splitting increases with the Sc ion content x. It has been shown that the low-temperature Mössbauer spectral lines of single crystals doped with Sc in a magnetically ordered state are broadened compared to the corresponding lines of the undoped SmFe3(BO3)4 ferroborate. This broadening is best approximated within the multilevel spin relaxation model. The Néel temperatures TN of the magnetic phase transition have been determined for all studied SmFe3 – xScx(BO3)4 samples. It has been found that the Néel temperature TN decreases nonlinearly with an increase in the Sc ion content x, and the model description of the three-dimensional magnetic interaction changes from the XY type to the Ising one.
Frolov et al. (Thu,) studied this question.