Crystal structure, dielectric and magnetic properties of Gd doped BiFeO3 multiferroics

Multiferroic Bi1-xGdxFeO3 ceramics (with x = 0.0, 0.05 and 0.10 coded as BFO/GDO, GD5 and GD10, respecfively) were synthesized via two stage solid-state reaction technique. Structural, magnetic and impedance measurements of prepared ceramics have been studied in a systematic way. X-ray diffraction studies and Rietveld analysis revealed a structure phase transition from rhombohedral (R3c) to orthorhombic (Pnma) at x >= 0.10. Due to the replacement of Fe3+ ions by Gd3+ ions (magnetically active), an increase in magnetization and coercive field is observed. For GD10 sample, a remnant magnetization (M-r) of 30 memu/g and coercive field (H-c) of 1.5 kOe were observed. The dielectric constant shows almost flat response with temperature for GD10 sample at different frequencies. Also at higher frequencies, the high values of epsilon' and low values of an delta for this material makes it suitable for device applications. The improvement in dielectric parameters and magnetic property is may be due to the presence of structural transformation resulting from the incorporation of Gd in the lattice of BFO.