Bi0.9Ba0.1Fe0.95O3 and Bi0.9Ba0.1FexTi0.05O3 (x=0.95, 0.925, 0.90) ceramics were prepared through conventional solid state reactions. X-ray diffraction analyses indicated that a high content of perovskite phase was obtained for all the four compositions. While the three (Ba,Ti)-codoped compositions all showed a higher resistivity than Bi0.9Ba0.1Fe0.95O3, and Bi0.9Ba0.1Fe0.925Ti0.05O3 had the best electrical and dielectric properties among the three (Ba,Ti)-codoped compositions, including the largest dielectric constant, the smallest dielectric loss at low frequency range, and the highest electrical resistivity. Magnetic hysteresis loop measurement revealed that the four compositions had similarly enhanced magnetic properties. It is concluded that much attention should be paid to fine composition adjustment when multiple elements are co-doped to BiFeO3 system.

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 .

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