Synthesis, characterization and dielectric properties of europium-doped barium titanate nanopowders

Abstract

Europium-doped cubic barium titanate (BT) nanocrystals with % [Eu/Ti] mol ratio varying from 0.05 to 0.25 were prepared through hydrothermal route. The nano nature of these powders was confirmed by XRD and TEM studies. Pellets were prepared after calcining the powders at 1000 degrees C for 2 h. These pellets were annealed at 200, 500, 700 and 1000 degrees C for 2 h at each temperature and used for dielectric measurements. Raman spectra of two typical pellets with %[Eu/Ti] Eu/Ti mol ratios of 0. 15 and 0.25 showed all the peaks characteristic of tetragonal BaTiO(3). Pure BT showed a low dielectric constant (DC) with a value of 398. Doping with small amounts of Eu resulted in many fold increase of DC values. A maximum value of 10576 at 1 KHz frequency was observed for the sample with % [Eu/Ti] mol ratio of 0.15. Lowering of Curie temperature T. (95 to 110 degrees C) was observed for pure as well as Eu-doped barium titanate. (C) 2007 Elsevier B.V. All rights reserved.