Percolation phenomenon in barium samarium titanate–silver composite Original Research Article

Ba4Sm9.33Ti18O54–Ag (BST–Ag) composites were prepared by a solid-state ceramic route and its dielectric properties were investigated in the vicinity of percolation threshold. The structure and microstructure of the composites were analyzed by X-ray diffraction along with optical and scanning electron microscopy observations. The effects of silver content and frequency on the dielectric properties of BST–Ag composites were studied using a LCR meter. The relative permittivity (εr) of the composite increases with silver content below the percolation limit and is in agreement with power law. A 0.14 volume fraction of silver loading increases the relative permittivity of the composite from 50 to 450 at 10 kHz. Addition of 0.15 volume fraction of silver increases the relative permittivity of the composite in the order of 105. It is found that the giant relative permittivity is almost constant for frequencies from 1 kHz to 1 MHz. This high εr composite offers the perspectives for application in electromechanical devices.