Characterization of tetragonal BaTiO3 nanopowders prepared with a new soft chemistry route

Preparation of BaTiO3 nanopowders (37-42 nm) is carried out by a controlled reconstructive thermal decomposition and crystallization from an amorphous polymeric precursor with polyvinyl alcohol (PVA) and sucrose at 400-600 degrees C in air. The Rietveld refinement of the XRD profile, processed at 600 degrees C in 2 h, infers the P4mm tetragonal crystal structure (95% of tetragonality) of the as prepared BaTiO3 nanopowders, with a=0.3994 nm and c=0.4024 nm. A cubic symmetry (Pm3m) of 5% in amount with a=4.0057 is also detected in addition with tetragonal symmetry. The characteristic tetragonal splitting of 002/200 XRD peaks also supports the tetragonal symmetry (c/a = 1.0075) of the as prepared BaTiO3 nanopowders. The average particle size (D) of the BaTiO3 powders, estimated with the help of the specific surface area, measured by BET method, is 39.91 nm. Average D value, calculated by Delta 2 theta(1/2) in the XRD peaks with the Debye Scherrer relation is similar to 40 nm. TEM study measures the particle size of the BaTiO3 powders with an average diameter of 37 to 42 nm. (c) 2006 Elsevier B.V. All rights reserved.