Structural, Electrical and Dielectric Properties of Li-Ni Ferrite–Polystyrene Thin Film Nano-Composites

Lithium nickel ferrite Li0.5Ni0.5Fe2O4 was synthesized by the sol–gel auto combustion method. The prepared ferrite was mixed with polystyrene with ratio 0.25:1(FP1), 0.50:1(FP2), 0.75:1(FP3) and 1:1(FP4) to get ferrite–polystyrene composite. The synthesized samples were characterized by x-ray diffraction, dielectric and direct current resistivity measurements. The x-ray diffraction pattern shows that the polystyrene is amorphous in nature. The diffraction peaks of ferrite–polystyrene composite become sharper and narrower by increasing the ferrite filler contents. Room temperature resistivity of the composites decreased significantly from 4.63 × 1013 Ω-cm to 3.67 × 109 Ω-cm with increasing ferrite content and temperature dependent resistivity decreased with increasing temperature. The dielectric constant increased as the concentration of ferrite was increased in the base sample. A maximum value of 23.60 was achieved for the last sample. Conversely, the increase in frequency results from the decrease in dielectric constant followed the Maxwell–Wagner model.