Effect of oxygen-ion motion on dielectric properties of Ba0.6Sr0.4TiO3 thick films

Abstract

The dielectric properties and electrical conductivity of porous Ba0.6Sr0.4TiO3 thick films prepared by screen printing were investigated. The thick films displayed several anomalous dielectric behaviors differing from dense Ba0.6Sr0.4TiO3 ceramics. The AC conductivity data obeyed the power-law relation of the universal dielectric response model, suggesting the existence of polarization resulting from hopping carriers in the thick films. Impedance spectroscopy analysis indicated two separate contributions for the thick films, both corresponding to the response of the grains. The activation energies of the two response processes were determined to be ∼1.0eV, manifesting that oxygen ions were the mobile carriers. The electrical heterogeneity of the grains was interpreted in relation to the porosity of the thick films. The dielectric anomalies of the thick films were linked to oxygen-ion motion. This work highlights an important effect of oxygen-ion hopping on the dielectric loss of the thick films in a wide frequency range.