Structural, dielectric, magnetic and magneto-dielectric properties of (1-x)BiFeO3-(x)CaTiO3 composites

(1 - x)BiFeO3-(x)CaTiO3 [(1 - x)BFO-(x)CTO, (x = 0, 0.1, 0.2 and 0.3)] composites were synthesized using sol-gel chemical method. Rietveld refinement was performed on X-ray diffraction data of all the samples reflect rhombohedral structure for x = 0, 0.1, 0.2 and the mixture of rhombohedral and orthorhombic structure for x = 0.3. The Field Emission Scanning Electron Microscope (FESEM) investigation confirms the microstructure consists of randomly oriented, homogenous, and non-uniform grains. The dielectric permittivity (epsilon) and tangent loss (tan delta) decreases with increasing frequency and show dielectric anomalies (as a hump) at different temperatures for different compositions. The incorporation of CTO decreases three order of leakage current (up to x = 0.2) and significantly improve the magnetization and magneto-dielectric coupling. The frequency-dependent ac conductivity obeys Jonscher's power law with large ac conductivity dispersion for higher frequencies with increasing CTO concentration. The variations of ac conductivity with the inverse of temperature obey the Arrhenius equation and show negative temperature coefficient of resistance (NTCR) behaviour. The ferromagnetic (FM) properties in BFO-CTO increases significantly with the increase of CTO concentration. The coercive field increases with increasing CTO concentration suggesting a competition between the antiferromagnetic and ferromagnetic ordering. The BFO-CTO samples exhibit large positive and negative magneto-dielectric coupling effect at room temperature.