Structure and dielectric properties of Eu-doped barium titanate ceramics

Eu-doped BaTiO3 ceramics (EBT) were prepared by the cold-pressing ceramic process on the basis of the formula Ra1-xEuxTi1-x/O-8(3) (x=0.01-0.05,0.10). The effects of Eu doping on the structure, microstructure, dielectric and ferroelectric properties of BaTiO3 ceramics were studied. EBT ceramics have a high density, a low porosity and a fine grain size of 0.7-1.0 mu m. As x <= 3%, EBT ceramics have a tetragonal perovskite structure. The Curie point decreases linearly at a rate of -11 degrees C/mol% Eu ions with increasing Eu content up to 0.04. However, at x >= 0.04, a secondary phase, Eu2Ti2O7, occurs and increases in concentration with increasing Eu, the Curie point remaining constant. The room-temperature dielectric constant of EBT ceramics (epsilon'(RT) = 1600-3100) shows a temperature-independent dielectric region below 50 degrees C at x >= 0.04, a frequency stability below 10(6) HZ and good ageing resistance behavior.