Microstructure and modified giant dielectric response in Ga‐doped La1.5Sr0.5NiO4 ceramics

The aim of this work is to improve the dielectric properties of giant permittivity La1.5Sr0.5NiO4 ceramics. The microstructure and dielectric properties of Ga‐doped La1.5Sr0.5NiO4 ceramics prepared by a solid state reaction method were investigated. It was found that Ga3+ doping ions have a remarkable influence on the microstructural evolution. La1.5Sr0.5Ni1 − xGaxO4 (x = 0, 0.1, and 0.3) ceramics exhibited giant dielectric constant with ε′ ~ 3.3–4.7 × 105 at 20 °C and 1 kHz. Interestingly, ε′ of La1.5Sr0.5Ni1 − xGaxO4 ceramics was enhanced by doping with Ga3+; whereas, the loss tangent (tanδ) decreased significantly. Reduction of tanδ is attributed to the increase in the total resistance, which is mainly governed by the sample–electrode contact resistance, and caused by a decrease in dc conductivity.

► Ga3+ doping has an influence on the microstructure of La1.5Sr0.5Ni1 − xGaxO4 ceramics.
► The sintered La1.5Sr0.5Ni1 − xGaxO4 ceramics exhibited ε′ ~ 3.3–4.7 × 105.
► ε′ of La1.5Sr0.5Ni1 − xGaxO4 ceramics was increased by doping with Ga3+.
► tanδ was greatly reduced by doping with Ga3+.