Magnetic Phase Transitions and the Dynamic Electric Polarization in the LaMn₂O₅ Compound

Abstract—Possible phase transitions to the ferromagnetic phase in the LaMn₂O₃ compound have been studied in the framework of a phenomenological approach based on a symmetry analysis. The conditions that parameters of the thermodynamic potential must satisfy to realize a second-order transition have been found. The line of the first-order phase transitions in this system and the critical point of the second-order phase transition line have been determined. It was shown that a dynamic electric polarization can form in the antiferromagnetic phase.