Effect of Cobalt substitution on the structural, electrical and magnetic properties of BaTiO3 ceramics

Cobalt doped BaTiO₃ (BaTi_1-xCo_xO₃) with x = 0, 5, 7.5, 10% have been synthesized by solid state reaction method and their structural, electrical and magnetic properties have been investigated. Structural characterization show that a multiphase ceramic containing both tetragonal and hexagonal structures are obtained for Co compositions from x = 5% to x = 10%. Ferroelectric and ferromagnetic properties have been observed in all the Co-doped BaTiO₃ ceramics at room temperature. The ferromagnetic hysteresis loop at room temperature is due to the formation of oxygen vacancies and their associated exchange interaction. The saturation magnetization (M_s) was 0.010 emu/g for x = 5%. Further, at x = 7.5%, it decreases and again start increasing upto ~ 0.013 emu/g for x = 10% with Cobalt concentration. However, ferroelectric hysteresis loop (P-E) is deteriorated (lossy type) with the increase of Co concentration above x = 5%. The dielectric characterization with frequency has also been carried out for all samples. The dielectric constant decreases with increasing Cobalt concentration.