We report results of dielectric and neutron diffraction measurements in zero field on magnetic ordering of weakly ferroelectric ErMn2O 5. Around the ferroelectric transition temperature of TC1 ∼ 38 K below TN1 = 44 K, we observed successive magnetic phase transitions from a two-dimensionally-modulated (2D) incommensurate magnetic (ICM) phase with the propagation vector q = (qx, 0, qz) to another 1D-ICM one with q = (qx, 0, 1/4) at T = 39.1 K, and then to a commensurate magnetic (CM) phase with q = (1/2, 0, 1/4) at T = 37.7 K. These two magnetic phase transitions (39.1 K and 37.7K) were found to be associated with an anomaly in the dielectric constant along the b axis. In addition, we found that in the case of a rapid-cooling procedure a low-temperature ICM state characterized by q = (1/2, 0, 0.265) shows up and coexists with the CM phase below TN2 = 11.5 K where evolution of magnetic order of the Er ions is inferred from measurements of the magnetoelectric effect. These observations indicate the strong coupling between ferroelectricity and magnetic orderins in this system.
- Neutron diffraction
- Successive magnetic phase transitions
ASJC Scopus subject areas
- Physics and Astronomy(all)