Effect of donor dopants cerium and tungsten on the dielectric and electrical properties of high Curie point ferroelectric strontium niobate

Abstract The perovskite-like layered structure ( PLS ) A 2 B 2 O 7 compound Sr 2 Nb 2 O 7 was doped with donor dopants CeO 2 and WO 3 to explore their doping effect on its A and B site, respectively. The doped ceramics were prepared by Spark Plasma Sintering. For Ce doping on the A site, single phase was maintained up to 5 mol% Ce ( x =0.05 in (Sr 1− x Ce x ) 2 Nb 2 O 7 ). For W doping on the B site, single phase was maintained at 2.5 mol% W ( x =0.025 in Sr 2 (W x Nb 1− x ) 2 O 7 ). The cerium and tungsten doping both inhibited grain growth and changed the grain morphology, leading to less anisotropic grains. The Curie point T c was obtained by measuring the temperature dependence of the dielectric constant and it was found to reduce for both Ce and W doped SNO. The W doped ceramics showed a diffuse ferroelectric phase transition at the Curie point. The DC resistivity of tungsten and cerium doped SNO increased compared to undoped SNO at temperatures below 700 °C. These results showed that both Ce and W had a strong influence on the dielectric and electrical properties of the Sr 2 Nb 2 O 7 ceramics.