Tunable magnetic properties of (Fe,Mn,Ga)3O4 spinel solid solution

https://doi.org/10.1016/j.jmmm.2026.173900

Single crystals of spinel Fe3−�Mn�O4 were prepared by the flux method using a solvent based on Bi2Mo3O₁₂-B2O3-Na2O with the addition of gallium oxide Ga2O3. The structural features of the obtained samples were studied by powder and single crystal X-ray diffraction analysis. According to EDX data, the obtained Fe3−�Mn�O4 crystals contain gallium in the amount of 12% per formula unit. Differential scanning calorimetry, specific heat study and temperature and field dependences of magnetization of the obtained single crystal showed a significant reduction of the ferrimagnetic phase transition (�� = 380 K) relative the parent Fe2MnO4 compound (�� = 560–580 K). The observed feature is, to a large extent, affected by the Fe/Mn/Ga ratio and demonstrates the possibility of the tuning the ferrimagnetic transition temperature over a wide temperature range. The flux technique for the single crystals synthesis enables precise variation of the Ga, Mn and Fe concentration in the (Fe,Mn,Ga)3O4 allowing one to create the material with the needed magnetic properties. The obtained spinel compound was studied in a wide temperature range: 300–770 K by DSC and 4.2–600 K by magnetization measurements. Along with the high-temperature ferrimagnetic phase transition, anomalies of the temperature dependence of the magnetization in small fields (about � = 50–100 Oe) accompanied by significant thermal hysteresis were detected in the ordered phase at much lower temperatures about � = 150–170 K that has not been observe