Effect of dysprosium substitution on crystal structure and physical properties of multiferroic BiFeO3 ceramics

The polycrystalline samples of multiferroic Bi1−xDyxFeO3 (x = 0, 0.1, and 0.2) were prepared by a modified solid state reaction method and characterized by X-ray diffraction, scanning electron microscopy, differential thermal analysis, dielectric and magnetic measurements. It was shown that the introduction of the Dy3+ ions stabilizes the perovskite structure and improves phase purity. The coexistence of the rhombohedral and orthorhombic phases was found to exist within the investigated concentration range 0.1 ≤ x ≤ 0.2. The changes and anomalies observed in dielectric response over a wide frequency range were correlated with the structural evolution and the development in microstructure. The SQUID measurements of the field-dependent magnetization at different temperatures demonstrated Dy doping to be a very effective method for inducing a weakly ferromagnetic state in the ferroelectric R3c phase of BiFeO3 in the absence of an external magnetic field.