Dielectric properties of TbMnO3 ceramics

The complex dielectric properties for ceramic samples of TbMnO3 were investigated as functions of temperature (100 K <= T <= 360 K) and frequency (100 Hz <= f <= 100 kHz). Two thermally activated dielectric relaxations were found with the activation energies of 0.30 and 0.22 eV for the high- and low-temperature relaxations, respectively. By means of complex impedance analysis the high-temperature relaxation was identified to originate from the internal barrier-layer capacitor effects related to the grain boundaries, and the low-temperature relaxation was ascribed to the dipolar effects induced by charge-carrier-hopping motions inside the grains. (c) 2007 American Institute of Physics.