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

Abstract

The Ba_0.8Sr_0.2Ti_1−2x Ga _x Nb _x O₃ (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_0.8Sr_0.2Ti_1−2x Ga _x Nb _x O₃ ceramics showed a higher dielectric constant with a lower DC-bias dependence as compared to previous study on co-doped BaTiO₃ ceramics. The Ba_0.8Sr_0.2Ti_0.20Ga_0.10Nb_0.10O₃ 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.