Synergetic effect of rare-earths doping on the microstructural and electrical properties of Sr and Ca co-doped BaTiO3 nanoparticles

Single-phase BST-BCT ceramic doped with different rare-earth materials (La, Gd, Dy, and Yb) have been prepared using a modified mechano-chemical activation technique. The modified BaTiO3 doped with different rare-earths elements have manifested improved characteristics and desirable application in the field of high-power pulse capacitors. In this work, a comparative study has been performed to analyze the effect of different rare-earths on the dielectric, ferroelectric, piezoelectric and electrical breakdown strength of already optimized Sr and Ca co-doped BaTiO3 ceramic. As predicted from finite element simulation, the doping of rare-earth may lead to a change in microstructure and surface characteristics of Sr and Ca co-doped BaTiO3 ceramic and therefore, an enhancement in electrical characteristics of the material. The addition of various rare-earths with the same cationic charge but different ionic radii has resulted in a significant change in morphology of BST-BST ceramic. The XRD results indicate that all the samples retain the parent perovskite tetragonal crystal symmetry, and there is no substantial change in the crystal structure compared to the base material. The addition of rare-earths has resulted in a decrease in transition temperature and significant changes in the electrical properties of modified BaTiO3 ceramic. Lanthanum and Gadolinium doping have resulted in an overall improvement in electrical characteristics; however, Dysprosium and Ytterbium doping deteriorated the same characteristics, which is mainly attributed to a significant change in the microstructure of the materials.