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

Abstract

The Ba0.8Sr0.2Ti1-2x 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 oC – 150 oC. The dielectric loss of all the co-doped ceramics was below 2 % within 25 oC – 200 oC. The Ba0.8Sr0.2Ti1-2x 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 Ba0.8Sr0.2Ti0.20Ga0.10Nb0.10O3 ceramics exhibited the best results of DC-bias dependence ≈ -24 %, dielectric constant at 100 kV/cm ≈ 560, and the dielectric constant at 0 kV/cm ≈ 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.