Tunable BST:MgO Dielectric Composite by Microwave Sintering

Abstract

Microwave sintering route was used for obtaining minimum chemical reactivity between the two phases (for sharp grain boundaries) and controlled microstructure in the composites of Ba_{1 − x}Sr_xTiO₃ (BST) and MgO. Composites of desirable compositions of ferroelectric BST and non-ferroelectric MgO were microwave sintered at a frequency of 2.45 GHz. Low dielectric constant, controlled microstructure, high relative density, and sharp grain boundary in BST:MgO composites were achieved. The depressed dielectric constant and tangent loss, high tunability and K-factor values are measured in the sintered composites. This paper describes the detailed studies on the microwave sintered BST:MgO composites and their tunable dielectric properties and microstructure development.

Keywords:

• Nano particle size
• BST
• BST:MgO
• composites
• field dependence
• tunability

Acknowledgement

Financial support of DARPA Grant # DABT 63-98-1-002 is acknowledged.