Effects of oxide additives on structure and properties of bismuth ferrite-based ceramics

Effects of oxide additives (Bi2O3, MnO2, La2O3, Sm2O3, SnO2, and Nb2O5) on structure and properties of 0.70Bi(1.05)FeO(3)-0.30BaTiO(3) ceramics were investigated. Their microstructure and electrical properties were dependent on the types and contents of oxide additives. A large piezoelectric constant (d (33)) of 135-200 pC/N together with a high Curie temperature of 454-504 A degrees C can be obtained in the ceramics with R-C phase boundary. Most of oxide additives can induce the formation of saturated P-E loops and butterfly-shaped S-E curves, while a pinched P-E loop and sprout S-E curve were observed in the Nb2O5-modified ceramics due to a completely suppressed E > (r)-T curve and seriously refined grain sizes. There were high bipolar strain values (S = 0.17%) under low driving electric fields for the addition of 0.5%mol Nb2O5. In addition, an enhanced magnetization of M (r) = 0.018 emu/g was achieved in the ceramics with 1.0% SnO2 due to the structure distortion and the breaking of spin helix structure.