Tailoring ZnO/CoFe2O4 nanocomposites: structure, optical, dielectric and magnetic study

Abstract

The structural, morphology, optical, magnetic and dielectric properties of the (ZnO)1–x(CoFe2O4)x, (x = 1, 3 and 5 wt%) nanocomposites synthetized by sonomechanical method were investigated using XRD, FE-SEM, HR-TEM, UV-visible, VSM and BDS. XRD analysis shows that, ZnO and CoFe2O4 acquired hexagonal and cubic phases, respectively. The optical band gap was reduced from 3.22 eV for pure ZnO to 3.15 eV after adding 5wt % of CoFe2O4. Addition of 1wt% CoFe2O4 to ZnO matrix showed a noticeable ferromagnetic behavior that was predominant in the prepared nanocomposites and confirmed by the convex Arrott–Belov–Kouvel curves. The dielectric constant, ε′, at higher frequencies of the investigated nanocomposites is relatively high (8–10) accompanied by low values of dielectric loss, ε″ ranging between 0.001 and 0.003 and hence very low values of the dissipation factor D (= ε″/ε′) making them applicable in the field of microwave shielding. On the other hand, the dc-conductivity, σ dc at 25 C shows a remarkable increase by Addition of 1wt% CoFe2O4 to ZnO matrix and decreases gradually with further increase of the ferrite. This indicates the effect of mobility and/or the number density of charge carriers on the conductivity. The investigation at higher temperature, 150 C, shows a gradual decrease in the conductivity with increasing CoFe2O4 content.