Structure and Dielectric Properties of Eu-Doped Barium Titanate Ceramics

Abstract

Eu-doped BaTiO 3 ceramics (EBT) were prepared by the cold-pressing ceramic process on the basis of the formula Ba 1 - x Eu x Ti 1 - x / 8 O 3 (x = 0.01-0.05, 0.10). The effects of Eu doping on the structure, microstructure, dielectric and ferroelectric properties of BaTiO 3 ceramics were studied. EBT ceramics have a high density, a low porosity and a fine grain size of 0.7-1.0 μm. As x≤3%, EBT ceramics have a tetragonal perovskite structure. The Curie point decreases linearly at a rat of -11°C/mol% Eu ions with increasing Eu content up to 0.04. However, -at x≥0.04, a secondary phase, Eu 2 Ti 2 O 7 , occurs and increases in concentration with increasing E u , the Curie point remaining constant. The room-temperature dielectric constant of EBT ceramics (e' R T =1600-3100) shows a temperature-independent dielectric region below 50°C at x≥0.04, a frequency stability below 10 6 Hz and good ageing resistance behavior.