Investigation of Ga-Nb co-doped barium strontium titanate ceramics for DC-bias free dielectrics

The Ba 0.8 Sr 0.2 Ti 1−2 x Ga x Nb x O 3 (0 ≤ x ≤ 0.10) ceramics were fabricated and the electrical properties were evaluated regarding DC-bias and temperature characteristics of the dielectric properties. The ceramics with x = 0.10 exhibited a stable dielectric constant with a change of–40% within 25 °C–150 °C. The dielectric loss of all the co-doped ceramics was below 2% within 25 °C–200 °C. The Ba 0.8 Sr 0.2 Ti 1−2 x Ga x Nb x O 3 ceramics showed a higher dielectric constant with a lower DC-bias dependence as compared to previous study on co-doped BaTiO 3 ceramics. The Ba 0.8 Sr 0.2 Ti 0.20 Ga 0.10 Nb 0.10 O 3 ceramics exhibited the best results of DC-bias dependence ≈−24%, dielectric constant at 100 kV cm −1 ≈ 560, and the dielectric constant at 0 kV cm −1 ≈ 735. The better results for the Ga–Nb co-doped BST ceramics might be due to the higher contribution of the ionic polarization in the BST base matrix resulting in a shallower potential energy curve.