Polycrystalline Bi(1-x)Dy(x)FeO(3) (x = 0.0, 0.03, 0.05, 0.07 and 0.1) ceramics have been prepared via a mixed oxide route. The effect of Dy substitution on the dielectric, ferroelectric, and magnetic properties of the BiFeO(3) multiferroic perovskite is studied. Experimental results suggest that in the Bi(1-x)Dy(x)FeO(3) system, increase of the Dy concentration leads to effective suppression of the spiral spin structure of BiFeO(3), resulting in the appearance of net magnetization. An anomaly in the dielectric constant (ε) was observed in the vicinity of the antiferromagnetic transition temperature. All compositions show saturated polarization-field (P-E) curves. As a result, improved multiferroic properties of Bi(0.9)Dy(0.1)FeO(3) ceramics with remnant polarization and magnetization (2P(r) and 2M(r)) of 7.98 µC cm(-2) and 0.024 emu g(-1), respectively, were established. An enhancement in remnant polarization after poling the samples in the magnetic field was evidence of magnetoelectric coupling at room temperature.

Pr modified Bi(0.9-x)La(0.1)Pr(x)FeO(3) (BLPFO-x, x = 0, 0.1 and 0.2) ceramics were prepared by the conventional method based on the solid state reaction of mixed oxides and a detailed study of electrical and magnetic properties of Pr modified bismuth ferrite (BLPFO) is reported. X-ray analysis shows the formation of a bismuth ferrite rhombohedral phase. Pr doping significantly increases the resistivity and leads to a successful observation of electrical polarization hysteresis loops. All the samples have been found to possess a spontaneous magnetic moment at room temperature which increases further at low temperatures. The strong dependence of remnant polarization and dielectric constant on the strength of magnetic field is a direct evidence of magnetoelectric coupling in BLPFO-2 ceramics.

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We have studied the multiferroic properties of Bi1−xEuxFeO3, x=0.03, 0.05, 0.07, and 0.1 ceramics prepared by conventional solid state reaction method. The substitution of Eu in place of Bi increases the magnetization at room temperature. An anomaly in the dielectric constant is observed at ∼400 °C which corresponds to TN. Room-temperature dielectric polarization–electric field (P-E) curves indicate that higher doped compositions exhibit saturated P-E loops with Pr (remnant polarization) of these BFO-based samples increasing with the degree of Eu modification. As a result, improved multiferroic properties of the Bi0.9Eu0.1FeO3 ceramics with remnant polarization and magnetization (Pr and Mr) of 11 μC/cm2 and 0.0347 emu/g, respectively, were obtained. The evidence of weak ferromagnetism and saturated ferroelectric hysteresis loops in Bi1−xEuxFeO3 system at room temperature makes it a good candidate for potential applications.

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