Dielectric Response of Ba_0.5Sr_0.5TiO₃-Mg₂SiO₄ Composites Synthesized by a Citrate Gel In-Situ Process

Abstract

(1-x)Ba_0.5Sr_0.5TiO₃(BST)-xMg₂SiO₄ (MS) composite ceramics have been synthesized in-situ via a citrate-nitrate combustion process, and their structure and effective dielectric response have been investigated. The compositions with x ≥ 0.3 formed a second phase Ba₂TiSi₂O₈, besides BST and MS phases. The BST-MS composites showed an uniform microstructure with MS particles homogeneously dispersed in BST particles. The temperature at the permittivity maxima of the composites was nearly unchanged with increasing the volume fraction of MS (ƒ_MS) from 0.1 to 0.4 and then slightly decreased with further increasing ƒ_MS. According to the modified effective medium approx-imation couple with the spherical inclusion model, the permittivity (ϵ_BST) of BST in the composites was strongly dependent on ƒ_MS, which was defined by the relation .

Keywords:

• Citrate-nitrate process
• in-situ synthesis
• composite
• effective dielectric response

Funding

This research was financially supported by the Natural Science Foundation of China (Grant no. 51202234).