Soft modes in HoFe2.5Ga0.5(BO3)(4) solid solution

Alexander Krylov, Svetlana Krylova, Irina Gudim & Alexander Vtyurin. Ferroelectrics. 2020, VOL. 556, 16–22

The condensation of two soft modes has been found when studying the Raman spectra of the solid solution HoFe2.5Ga0.5(BO3)4 in the temperature range from 7 to 350 K. The first high-temperature soft mode is associated with the structural phase transition from the R32 phase to the P3121 phase. The second soft mode is related to the reveal of the phonon-magnon interaction during magnetic ordering in the crystal. The temperatures of the structural phase transition T1 ¼ 266 K and the magnetic phase transition T2 ¼ 28 K are established. Experimentally interaction between the structural phase transition order parameter fluctuations and the magnetic order parameter fluctuations was found.