Giant dielectric response with reduced loss in ceramics with nominal composition of La1.5Sr0.5NiO4-SiO2

Abstract

Structures and dielectric properties of La1.5Sr0.5NiO4 ceramics with different contents of SiO2 additives were investigated. The La1.5Sr0.5NiO4 particles were dispersed into SiO2 matrixes via a sol-gel process, while the homogeneous distribution was destroyed by the reaction between La1.5Sr0.5NiO4 and SiO2 during the sintering process, so the composite ceramics consisted of La1.5Sr0.5NiO4, La9.33Si6O26 and NiO phases. The dielectric constants at room temperature varied slightly, while the dielectric losses could be suppressed with a moderate amount of SiO2 additive. Temperature-independent giant dielectric constant with low loss was achieved in the ceramics with nominal composition of La1.5Sr0.5NiO4–0.80SiO2. Based on the analysis of impedance spectra, the giant dielectric response in the composite ceramics was attributed to the combination of the small polaronic hopping and Maxwell-Wagner effect.