Structural, Raman and electrical studies of 2 at.% Dy-doped NBT

The effects of Dysprosium addition to sodium bismuth titanate (NBT) on structure and electrical properties are reported. The polycrystalline ceramics of pure NBT and Na0.5(Bi0.98Dy0.02)0.5TiO3 (2DyNBT) were prepared via solid state reaction and sintering. A pure perovskite structure was obtained for both compositions. However, Raman measurements suggest that the introduction of Dy3+ creates local disorder in the structure without modifying long-range symmetry. The temperature dependant dielectric properties exhibit a number of anomalies that are more pronounced in the case of 2DyNBT because of the higher local disorder. These anomalies are discussed in terms of ferroelectricaantiferroelectric phase transition mechanisms. Because of the higher resistivity of 2DyNBT temperature dependant ferroelectric measurements were possible clearly confirming the existence of a ferroelectricaantiferroelectric phase transition in this system.