The effect of Ba²⁺ doping on the structure of SrBi₄Ti₄O₁₅

Abstract

In this paper, bi-layered structural ferroelectric materials Sr_1−x Ba _x Bi₄Ti₄O₁₅(SBBT) (x=0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) were prepared using sol–gel method. The stable precursors were fabricated by mixing the salts of strontium (Sr), barium (Ba), bismuth (Bi) and titanium butoxide in acetic acid together with ethanolamine as a catalyzer and acetylacetone as a stable agent. The structural evolution of SBBT after Ba²⁺ doping was studied. The experimental results confirm that complete solid solutions of SrBi₄Ti₄O₁₅ and BaBi₄Ti₄O₁₅ are formed. The perovskite lattice will expand after the doping of Ba²⁺ because of the difference of ionic radii of strontium and barium cations, which will lead to increasing of the lattice spacing. With the increase of the content of Ba cations the grain size of SBBT powder increases, the granularity distribution widens and average particle size of SBBT powder also increases. The average particle size of SrBi₄Ti₄O₁₅ and BaBi₄Ti₄O₁₅ is 82.5 and 165.2 nm, respectively.