Dielectric, electric modulus, ferroelectric and magnetic properties of Bi1−xGdxFeO3 ceramics

Bi_(1-x)Gd_xFeO₃ (BGFO, x=0.05-0.3) crystallites were synthesized by the microwave hydrothermal method. Then, the powders were sintered into shaped BGFO ceramics. The results showed that Gd³⁺ could dramatically affect the structural, ferroelectric and magnetic behavior of BiFeO₃ ceramics. X-ray diffraction results indicated that pure BGFO ceramics could be obtained. The morphologies of the BGFO are investigated by scanning electron microscopy. All the samples are well compact without pores and the grain are agglomerated. The dielectric constant increases and dielectric loss decreases with increasing Gd³⁺ contents. The value of Ac-conductivity of Bi_0.95Gd_0.05FeO₃ at 1000 kHz is in the order of ~10^-4, which is several orders of magnitude larger than that of Bi_0.7Gd_0.3FeO₃. The double peaks appearing in the plots of M\´ and M" with frequency for x=0.30 confirms the coexistence of grainand grain boundary effects. The introduction of Gd into BiFeO₃ ceramics was found to improve the saturated magnetization value dramatically.