Dielectric and Ferroelectric Properties of La-Doped SrBi₂Nb₂O₉ Ceramics

Sr_1-xLa_2x/3Bi₂Nb₂O₉ (0 ≤x≤ 0.2) ceramic samples are prepared by the solid-state reaction method. Their structure, dielectric and ferroelectric properties are investigated. The incorporation of La³⁺ improves the densification and decreases the grain size of the ceramics without changing the crystal structure. The remanent polarization 2P_r increases with increasing La content and reaches a maximum value of 22.8μC/cm² at x=0.125, which is approximately 60% larger than that of pure SrBi₂Nb₂O₉. The Curie temperature keeps almost unchanged at a value of about 440°C. The relationship between doping and the ferroelectric and dielectric properties are discussed.