Structure and dielectric studies of nano-composite Fe2O3: BaTiO3 prepared by sol-gel method

Nano-structure pure barium titanate (BaTiO3) and that was doped with iron oxide (Fe2O3), have been prepared by sol-gel method, using barium acetate (Ba(Ac)(2)) and titanium butoxide (Ti(C4H9O)(4)), as precursors. The as-grown prepared samples by sol-gel technique were found to be amorphous, which crystallized to the tetragonal phase after synthesized at 750 degrees C in air for 1 h as detected from the XRD patterns. The XRD data were confirmed by transmission electron microscope (TEM). The dielectric properties namely; dielectric constant (epsilon') and loss tangent (tan delta) in the frequency range between 42 Hz and 1 MHz, at range of temperature 25-250 degrees C were investigated. The temperature dependence of epsilon' and tan 5 for the undoped and doped materials, at 1 kHz, was also investigated. As a result, tan delta increased rapidly with decreasing temperature below 125 degrees C (Curie temperature) while above this temperature, tan delta shows temperature independent. As a result, below and above Curie temperature, ferroelectric phase and paraelectric phase of BaTiO3 can be obtained, respectively. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.