Abstract:
To study the dependence of the properties of ternary oxides (Mn,Fe,Ga)$_2$O$_3$ with the bixbyite structure on the composition, the temperature dependences of the magnetization and $ac$ magnetic susceptibility of two single-crystal samples of different compositions obtained using the flux method were analyzed. A detailed study of the structure was carried out using single-crystal X-ray diffraction analysis, and the changes in structural parameters depending on the composition were analyzed. The $dc$ magnetization and $ac$ magnetic susceptibility of Fe$_{1.1}$Mn$_{0.76}$Ga$_{0.14}$O$_3$ and Fe$_{0.65}$Mn$_{1.1}$Ga$_{0.26}$O$_3$ bixbyites have been studied. Despite the qualitatively similar behavior of the magnetic properties, significant differences were also found, despite a small difference in the Mn/Fe/Ga ratio in the samples under study. It is shown that both compounds experience two successive low-temperature magnetic phase transitions from the paramagnetic phase at $T$ = 20–32 K as the temperature is lowered. Calculations of the Mydosh parameter for the detected phase transitions showed different degrees of ordering in the compounds under study.
Keywords:transition metal oxides, magnetic phase transitions, spin glass state, bixbyite.