Frozen Superparaelectric State of Local Polar Regions in GdMn2O5 and Gd0.8Ce0.2MnO5

A comparative study of the dielectric properties and electric polarization of multiferroics GdMn 2 O 5 and Gd 0.8 Ce 0.2 MnO 5 has been carried out in the temperature range 5–330 K. The polarization properties in the ferroelectric state that forms due to a charge ordering and exchange striction have been studied at T ≤ T C = 30 K. The properties of the restricted polar phase separation domains formed in the crystals containing ions Mn 3+ and Mn 4+ have been studied, too. These domains exhibit the electric polarization in the temperature range from 5 K to some temperatures T f ≫ T C . Such a high-temperature polarization is due to the frozen superparaelectric state of the restricted polar domains.