Abstract: Sm substituted 0.8BaTiO₃-0.2Bi_0.5K_0.5TiO₃ lead free ceramic materials with composition 0.8Ba0.2 (Bi_0.5(1-x)Sm_0.5xK_0.5)TiO₃ (x=0.01,0.03,0.05) were prepared by conventional solid state reaction method and followed by high energy ball milling process. The X-ray diffraction studies confirm the tetragonal structural of the material at the room temperature. With increase of Sm substitution, density is decreasing. Microstructure studies were done with the help of scanning electron microscope. Temperature and frequency dependant dielectric studies indicate that dielectric constant decreasing with the substitution of Sm. Sm substitution effects the Curie temperature and it is decreasing with increase of Sm substitution. Relaxor behaviour is observed in all the Sm substituted samples. Degree of diffuseness is calculated from the modified Curie-Weiss law and it was found to be increase with the substitution of Sm.

Keywords: lead free ceramics; BaTiO₃; Bi_0.5K_0.5TiO₃; dielectric.