Effects of Ba and Ti co-doping on BiFeO3 multiferroic ceramics optimized through two-step doping

Abstract

Ceramics of Bi 0.9 Ba 0.1 Fe 0.925 Ti x O 3 (x = 0.0625, 0.08125, 0.0875, and 0.11) were prepared according to two doping strategies: one is called single-step doping in which Ba and Ti were doped together in calcination, while the other one is called two-step doping in which Ba and Ti were doped in calcination and sintering, respectively. Compared with samples prepared with single-step doping, those prepared with two-step doping have obviously different XRD patterns and small grains, and are dramatically improved in dielectric loss, resistivity, and remnant magnetization. A low dielectric loss of 0.05 at 10 3 Hz, a high resistivity of 4×10 12 Ω·cm, and a large remnant magnetization of 1.5 emu/g, have been obtained simultaneously for Bi 0.9 Ba 0.1 Fe 0.925 Ti 0.11 O 3 prepared with two-step doping. The contrast between these two doping strategies clearly reveals the importance of establishing a proper doping strategy when two or more elements are co-doped to BiFeO 3 .

Complete Phase Change of Y₂NiMnO₆ Ceramics Doped with TiO₂ at High Temperature

“…Low proportions of dopant can introduce strain within the crystal phase structure detectable by X-ray diffraction, without changing the main phase. A dual doping process of BiFeO 3 perovskite with Ba and TiO 2 between two calcining steps resulted in Ti concentrating in grain boundaries and suppression of grain growth(refining) leading to improvement of resistance and magnetic properties [5]. Other dopants can also concentrate in the grain boundaries preventing coarsening at high temperatures [6].…”