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

Abstract

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 .

Keywords

• lead free
• ferroelectrics
• perovskites
• solid state route