Enhanced dielectric, magnetic and magnetoelectric properties in 0.5BaFe12O19 - xBaTiO3 - (0.5-x)CoFe2O4 composites

Abstract

(0.5)BaFe12O19 - xBaTiO3 - (0.5-x)CoFe2O4; (x = 0.1, 0.2, 0.3 & 0.4) composite system was developed through conventional solid-state technique. XRD with Rietveld refinement confirmed pure tri-phasic composites with no impurity. The microstructure of samples has inhomogeneous grain packing with average size of grains ∼0.5 μm and typically decreased with BaTiO3 increment. The dielectric constant showed low-frequency dispersion and increased with BaTiO3 increment, hence maximum at 400 °C for composite x = 0.4 (∼2.8 × 103 at 1 kHz). Composites are ferrimagnetic in nature along with presence of firm exchange coupling among BaFe12O19/CoFe2O4 ferrite phases. The samples are multiferroic owing to typically high magnetoelectric coupling coefficient which increased with BaTiO3 increment, thus composite x = 0.4 attains highest value of 4.56 mV/cm.Oe on application of ac magnetic field (Hac = 45 Oe). The results indicate that the composites are suitable for magnetic field sensors and memory storage devices.