Effect of Sr2+doping on the phase transition of BaTiO3 lead-free ferroelectric ceramics

The single phase Ba 1−x Sr x TiO 3 (x = 0, 0.4, 0.8) ceramic compositions were fabricated through solid state (mixed oxides) method calcined at 850 °C and sintered at 1200 °C in air. The XRD patterns revealed the single phase BaTiO 3 composition with a space group of pm-3m. The shifting of the (1 0 0) XRD peak to higher 2 θ values is accredited to the substitution of comparatively smaller ion of Sr 2+ (1.4 Å) for larger Ba 2+ (1.6 Å) ion following the Braggs diffraction law (2dsin θ  = m λ ). The phase transition or Curie point from polar ferroelectric phase to non-polar paraelectric phase of Ba 1−x Sr x TiO 3 was reported to decrease with increasing Sr 2+ content in Ba 1−x Sr x TiO 3 compositions. The value of the dielectric constant decreased with increasing the content of Sr 2+ , which may be attributed to the substitution of comparatively smaller ion of Sr 2+ for Ba 2+ in the perovskite structured Ba 1−x Sr x TiO 3 .