Low temperature sintering and nonlinear dielectric properties of lithium-doped Ba 0.6 Sr 0.4 TiO 3 thick films prepared by tape-casting

The thick films with nominal composition of Ba 0.6 Sr 0.4 TiO 3 +0.4 wt% Li 2 O were prepared through tape casting. The structure and nonlinear dielectric properties of the resulting thick films were investigated within the sintering temperature range of 1050–1100 °C. The thick film specimens sintered at the relatively low temperatures exihibited dense and no crack microstructure due to the addition of sintering aid Li 2 O and modified process technology. An obvious influence of sintering temperature on the microstructure and nonlinear dielectric properties was detected. The discrepancy in nonlinear dielectric properties among the specimens sintered at different temperatures was qualitatively interpreted in terms of interfacial charge accumulation and defect dipole reorientation. Sintering at 1080 °C was determined to be preferred for the specimens with regard to the nonlinear dielectric properties. At room temperature, the specimen attained a dielectric constant of 3050 and a relatively low dielectric loss tangent of 0.15% at 10 kHz together with a extremely large figure of merits (FOM) of 580 and a tunability of 88% at 10 kHz and 200 kV/cm.