Percolation phenomena of dielectric permittivity of a microwave-sintered BaTiO₃–Ag nanocomposite for high energy capacitor

In the present study, the Alkoxide-Hydroxide sol-gel process is utilized for the synthesis of barium titanate-silver (BaTiO₃–Ag) nanocomposite in an inert atmosphere. The high value of dielectric constant having less tangent loss is obtained along with increasing conductivity with Ag content. Moreover, by the inclusion of the conductive phase in BaTiO₃, the increasing value of dielectric properties with decreasing Curie temperature is investigated. Sintering of composites was done at 1100 °C for 20 min by using microwave sintering, to improve the densification of ceramic nanocomposites in lesser time with uniform grain size. By increasing the silver content, dielectric constant and tangent loss increased until the percolation threshold (∼5% Ag) achieved and suppression of formation of conducting path in composite occurred due to adhesion of silver on barium titanate. Also, at T_c in BaTiO₃–Ag (3.5%), the highest value of dielectric constant (ε_r) (∼9 × 10⁴ with tangent loss ∼0.06; several times larger than pure BaTiO₃) was obtained due to well dispersion of silver particles in BaTiO₃ matrix.