| Abstrakt: |
Ba1−xDyxTi1−xScxO3ceramics, 0 ≤ x≤ 0.075, were prepared and the influence of Dy and Sc co-doping on the ferroelectric, electrical and structural properties of BaTiO3(BT) investigated. A solid solution limit of x 0.05 was established using X-ray diffraction, and all compositions x≤ 0.05 were tetragonal at room temperature. Fixed-frequency capacitance measurements showed the temperature of the cubic to tetragonal phase transition, TC, decreased non-linearly with increasing xand the associated permittivity peak broadened, with frequency-dependent ‘relaxor’-type behaviour observed for cubic x= 0.075. In addition, the magnitude of the relative permittivity at TCshowed a negative dependence on x, decreasing from ∼11 700 for x= 0 to ∼6950 for x= 0.05. In contrast to the non-linear decrease in TC, the tetragonal to orthorhombic and orthorhombic to rhombohedral phase transition temperatures decreased linearly at rates of ∼40 and ∼28 °C mol%−1of DyScO3, respectively. The effect on the ferroelectric properties of BT was to quadruple the coercive field, from ∼0.9 kV cm−1for x= 0 to ∼4.4 kV cm−1for x= 0.025, without affecting the remnant polarisation, ∼10 to 11 µC cm−2for x= 0 to 0.025. Finally, the non-linear decrease in TCis discussed in terms of the contributions of the mean size and statistical variance of the cations on the Aand Bsites of the perovskite, ABO3, lattice and the replacement of Ti4+with Sc3+cations. [ABSTRACT FROM AUTHOR] |
