Why Sn doping significantly enhances the dielectric properties of Ba(Ti1-xSnx)O3

Abstract

Through appropriate doping, the properties of BaTiO3-based ferroelectrics can be significantly enhanced. To determine the physical process induced by the doping of Sn atoms in Ba(Ti0.8Sn0.2)O3, we performed high-resolution scanning transmission electron microscopy experiments and observed that the regions with low Sn content formed polar nano regions (PNRs) embedded in the matrix in Ba(Ti0.8Sn0.2)O3. The interactions among Sn, Ti, Ba and O atoms were determined using first principles calculations. Based on the characteristics of the electronic structure and crystal lattice strain fields, the effects of doping with Sn were investigated. The Sn doping not only changed the electronic structure of the crystal but also increased the dielectric properties of the PNRs. Moreover, the Sn doping was also responsible for the diffuse phase transition of the Ba(Ti1-xSnx)O3 material. The effects mentioned in this paper are universal in lead-free ferroelectrics, and similar elements such as Sb, Mg, and Zr may have the same functions in other systems. Thus, these results provide guidance for the design of the doping process and new systems of ferroelectric or relaxor materials.

Electrocaloric response near room temperature in Zr- and Sn-doped BaTiO 3 systems

“…ε m reaches a maximum of 9500 for 0.7BZT18-0.3BST11. As previously mentioned, doping Zr and Sn causes the system to crossover from a normal ferroelectric to a relaxor with a diffuse phase transition, which consequently lowers the transition temperature [20].…”

Lead palladium titanate: A room-temperature multiferroic

“…[28,29] Upon Pd doping, the measured ferroelectric T c values were lower. This can be rationalized by changes in the unit cell induced by doping with Pd 4+ ion, whose radius (0.615 Å [27]) is slightly larger than that of Ti 4+ (0.605Å [27]).…”

“…Therefore undoped nanoregions expand under the stress of the matrix, [28] which creates more space between Ti atoms and the oxygen octahedra allowing larger off-center displacements directly related to polarization strength. [28,29] Upon Pd doping, the measured ferroelectric T c values were lower.…”

Crystalline Structure, Defect Chemistry and Room Temperature Colossal Permittivity of Nd-doped Barium Titanate

“…Inorganic ceramic materials with high dielectric constant have received extensive attention, due to their application in multilayer ceramic capacitors (MLCC)6 and inorganic-organic hybrid flexible composite films7. The dielectric properties of inorganic ceramic materials can be improved via chemical modification89 and/or grain-size engineering10. Among them, rare-earth element(s) doped BaTiO 3 (RE: BaTiO 3 ) has been considered as one of the most suitable materials for ferroelectric capacitors, because of its colossal dielectric constant (CDC)11.…”