Structural, microstructure, magnetic, and dielectric characterization of BaFe12O19/NiFe2O4ferrite nanocomposites

BaFe12O19 and NiFe2O4 ferrite powders were synthesized separately using the sol gel auto-combustion method, and physically mixed in various weight ratios (100:0, 50:55, 40:60, 20:80, 0:100). The nanocomposites were heated at 1000 °C and characterized using XRD, SEM, VSM, and dielectric techniques. XRD analysis confirmed the presence of both hexagonal (BaFe12O19) and cubic (NiFe2O4) phases in the prepared nanocomposites. SEM micrographs revealed notable changes in the grain morphology and grain size with increasing nickel ferrite content. Magnetic hysteresis studies indicated that all BaFe12O19/NiFe2O4 nanocomposites exhibit multi-domain nature as reflected by the squareness ratio (<0.5). The coercivity varied from 0.0216 T to 0.0813 T, while saturation magnetization varied between 27.3 Am2/kg to 38.2 Am2/kg. The nanocomposite containing the equal proportion (50%) of BaFe12O19 and NiFe2O4 exhibited the highest dielectric constant (ε' = 60 at 100 Hz). Typical ferrite behavior was observed in the frequency-dependent AC conductivity, dielectric constant, dielectric loss, electric modulus, and impedance responses. The 50% nanocomposite shows a single semi-circular arc in the higher frequency region, where other nanocomposites show double arcs at lower and higher frequency regions.