Dielectric Properties and Phase Transition in Sb/Mn and La/Mn CODOPED BaTiO3 Ceramics

Donor/acceptor Sb/Mn and La/Mn codoped BaTiO 3 systems, obtained by solid state reactions, were investigated regarding their microstructure characteristics, dielectric permittivity and dielectric response in a ferroelectric and paraelectric regime. The concentrations of 0.5 and 1.0 at% Sb 3+ and La 3+ were used for doping, while a content of Mn-ions was kept constant at 0.05at%. The specimens were sintered at 1290, 1320 and 1350°C. Microstructural and compositional studies were done using SEM equipped with EDS. Fine-grained ferroelectric ceramics, with grain size around 1-2 μm, were obtained for both types of samples sintered at temperature below 1350°C, while at 1350°C abnormal grain growth occurs in La/Mn-doped systems. The electrical resistivity of La/Mn and Sb/Mn doped BaTiO 3 compositions were in the range of 10 8 to 10 10 Ω cm . A sharp permittivity maximum occurred at Curie point with low content of dopants and broadened slowly with increasing donor/acceptor ratio. The specimens demonstrated a Curie-Weiss behavior in a paraelectric regime.