Dielectric relaxations of LaAlO3 ceramics over broad temperature range

LaAlO3 ceramics were prepared via the solid-state reaction route. The low-frequency dielectric properties were investigated in detail in a broad temperature range from 100 to 1100 K. We found that LaAlO3 shows a flat dielectric plateau independent of frequency and temperature below 500 K. When temperature higher than 500 K, two thermally activated dielectric relaxations were observed with the activation energy of 1.13 eV for the low-temperature relaxation and 1.9 eV for the high-temperature relaxation. Our result indicates that the low-temperature relaxation is related to the bulk effect due to hopping motions of oxygen vacancies and the high-temperature relaxation was associated with the Maxwell-Wagner relaxation due to the interface effect. Crown Copyright (C) 2012 Published by Elsevier B. V. All rights reserved.