57Fe Mössbauer Spectroscopy Study of SmFe3 –xAlx(BO3)4 (x = 0–0.28) Multiferroics
https://doi.org/10.1134/S0021364024604998
SmFe3 – xAlx(BO3)4 multiferroic single crystals with x = 0–0.28 have been studied in the temperature range T = 3.8−298 K using 57Fe Mössbauer spectroscopy and X-ray diffraction analysis. An increase in the Mössbauer hyperfine quadrupole splitting with the content of aluminum x impurities has been found. For all studied samples, the Mössbauer Debye temperatures ΘM of iron ions have been determined in good agreement with the values for iron ions calculated from X-ray diffraction data. It has been shown that the low-temperature Mössbauer spectral lines of single crystals doped with Al 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 – xAlx(BO3)4 samples. It has been (found that the Néel temperature TN decreases nonlinearly with an increase in the content x of aluminum, and the type of three-dimensional magnetic ordering changes from planar to Ising.