Phase coexistence evolution of nano BaTiO3 as function of particle sizes and temperatures

Using high resolution synchrotron x-ray diffraction, we systemically study the crystal structure evolution of nano BaTiO3 as function of temperatures and particle sizes. In the temperature range from 200 K to 450 K, the nano BaTiO3 with different particles in the range from 5 nm to 100 nm are phase coexisting. The phase fraction evolutions of different nano BaTiO3 indicated that there is an anomaly at particle size around 20 nm, a phase reentrance taking place. The competition of the shear stresses and the compressive stresses on the particle surface, and the delicate balance between them are responsible for the reentrance phenomenon. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751332]