Effect of Dy³⁺ Substitution on Structural and Dielectric Properties of 0.8BaTiO₃-0.2Bi_0.5K_0.5TiO₃ Lead Free Ceramics

Abstract

Dysprosium (Dy³⁺) ion substituted 0.8BaTiO₃-0.2Bi_0.5K_0.5TiO₃ (here after abbreviated as BTBKT-20) lead free ceramic materials with composition 0.8BNa0.2(Bi_0.5(1-x)Dy_0.5xK_0.5)TiO₃ (where 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 structure of the material at the room temperature. Microstructure studies have been carried out with the help of scanning electron microscope. Temperature and frequency dependent dielectric studies indicate that dielectric constant decreasing with the substitution of Dy³⁺. The substitution of Dy³⁺ effect the Curie temperature and it is decreasing with increase of Dy³⁺ substitution. Relaxor behavior is observed in all the Dy³⁺ substituted samples. Degree of diffuseness is calculated from the modified Curie-Weiss law and it has been found to be increasing with the substitution of Dy. AC conductivity is calculated and it is found to be obey the universal Jonscher’s Power law.

Keywords:

• Lead free ceramics
• BaTiO₃
• Bi_0.5K_0.5 TiO₃
• dielectric