Dielectric relaxation in LuFeO3 ceramics

LuFeO3 ceramics were prepared, and the dielectric characteristics were investigated together with the structure. A giant dielectric constant step (8000 at 10 kHz, 7200 at 100 kHz, and 4000 at 1 MHz) very similar to that in LuFe2O4 was observed. The dielectric constant dropped quickly when the temperature decreased through a critical temperature which increased significantly when the frequency increased. A very high relaxor-like dielectric peak with strong frequency dispersion was also observed in a higher temperature range. Two obvious corresponding dielectric relaxation peaks were observed on the curve of dielectric loss vs temperature, and all these dielectric relaxations followed the Arrhenius law. The Fe2+/Fe3+ mixed-valence structure and the oxygen vacancy primarily governed these relxor-like dielectric behaviors. However, the present ceramics are not relaxor ferroelectric. (C) 2009 Elsevier Ltd. All rights reserved.