Effect of Co₂O₃ Doping on the Dielectric and Tunable Properties of Ba_0.6Sr_0.4TiO₃ Ceramics

Co₂O₃-doped Ba_0.6Sr_0.4TiO ₃ ceramics were fabricated by the traditional fabrication technique and their structural, surface morphological, dielectric and tunable properties were investigated. X-ray diffraction (XRD) studies revealed that all the specimens exhibited a perovskite structure without the existence of the second phase. A strong correlation was observed between the average grain size and Co₂O₃ doping concentration and the results indicate that Co³⁺ behaves like a grain-growth inhibitor. The addition of Co ₂O₃ lowers the dielectric constant and the Curie temperature as well. Both the dielectric loss and tunable properties were modified by the addition of Co₂O₃. When the doping content is up to 2 wt%, the tunability is 14.5% while the dielectric constant decreases from 3000 to 1795.