Structure and dielectric characteristics of continuous composition spread Ba1−xSrxTiO3 thin films by combinatorial pulsed laser deposition

Ba1−xSrxTiO3 (0≤x≤1, BST-x) continuous composition spread thin films were grown on SrTiO3 substrates buffered by La0.9Sr1.1NiO4 (LSNO) electrodes using combinatorial pulsed laser deposition. The effects of Sr concentration on the structure and dielectric properties of the Au/BST-x/LSNO capacitors were investigated. X-ray diffraction patterns and reciprocal space maps revealed that both the in-plane and out-of-plane BST-x lattice parameters decreased with the increment of Sr content. Impedance measurements showed that the dielectric constant and tunability simultaneously changed with Sr concentration and reached the maximum at about x=0.5, which is comparable to that of BST-x individual thin films or bulks. Our results showed the large potential of combinatorial method in optimizing materials properties and even finding new materials.