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Ba and Dy co-doped at A-site BiFeO3 ceramics have been successfully synthesized by a conventional solid state reaction technique. The analysis of crystal structure was done by X-ray diffraction (XRD) pattern. The Rietveld refined XRD pattern of prepared sample confirmed co-existence of Rhombohedral and Orthorhombic phases with R3c and Pnma space group, respectively. The low values of χ², Rp and Rwp obtained from Rietveld refinement shows good agreement between observed and calculated values. There is suppression of growth of secondary phases due to doping of small sized Dy3+ in place of Bi3+ ion. It has been found that the values of dielectric constant and dielectric loss increase with increase in temperature at different frequency. This is because of increase in number of charge carriers and their mobilities due to the thermal activation. Frequency dependence of dielectric constant and dielectric loss is understood using Maxwell Wagner model. [ABSTRACT FROM AUTHOR]

Multiferroic xNa0.5Bi0.5TiO3-(1-x)ZnFe2O4 (x=0.10, 0.20) composites were prepared by conventional solid state reaction method. Rietveld analysis of XRD data shows that samples exhibit both cubic (Fd-3m) and rhombohedral (R3c) crystal structure. Structural parameters and unit cell volume of samples vary with composition. The dielectric constant and dielectric loss (tanδ) display dispersion at low frequency due to space charge polarization and inhomogeneity in the composites. Magnetic analysis depicts the antiferromagnetic behavior of composites and magnetization is enhanced with the introduction of ferrite (ZnFe2O4) phase. [ABSTRACT FROM AUTHOR]