Dielectric relaxations in multiferroic La2Ti2O7 ceramics

La2Ti2O7 ceramic samples were prepared via conventional solid-state reaction route. The dielectric properties of La2Ti2O7 were investigated as functions of temperature (113-1073 K) and frequency (100 Hz(-1) MHz). Our results revealed that La2Ti2O7 ceramics exhibit intrinsic dielectric response with a dielectric constant of similar to 57 in the temperature range below 250 K. Three thermally activated dielectric relaxations were observed when the temperature higher than 250 K. The low-temperature relaxations R1 with the activation energy of 0.38 eV is found to be a polaron relaxation results from hopping holes. The high-temperature relaxations R2 and R3 are related to the conduction progress associated with the singly and doubly ionized oxygen vacancies, respectively. (C) 2015 Elsevier B.V. All rights reserved.