Dependence of the Crystal Structure on Particle Size in Barium Titanate

The effect of the sample particle size on the crystal structure and the Curie temperature of BaTiO 3 powder has been investigated in the particle size range 0.1 to 1.0 μm. The transformation from tetragonal to cubic symmetry occurs at a critical particle size of 0.12 μm at room temperature, and the Curie temperature drops below room temperature at the critical particle size.