Based on ab initio calculations for a number of the Ba cSr (1-c)TiO 3 (BST) super-lattices, we developed a thermodynamic approach to these solid solutions. In particular, we calculate the BST phase diagram and show that at relatively low temperatures (below 400 K for c=0.5 and 300 K for c=0.1) the spinodal decomposition of the solid solution occurs. As a result, we predict for small Ba concentrations formation of BaTiO 3 nanoregions in a predominantly SrTiO 3 matrix and vice versa, which is confirmed by the Raman, polarization, ultrasonic, neutron diffraction, and diffusion experiments.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1 Jan 2005|