Structural, dielectric and optical properties of CoFe2O4/Organoclay composites prepared by sol-gel autocombustion

ODA-MNT, an organomodified montmorillonite (2, 4 and 6 wt%) supported CoFe 2 O 4 Nano-composites were synthesized using sol-gel autocombustion method. The structural and microstructural characterizations of the samples were performed using XRD, Raman spectroscopy and SEM techniques. The dielectric and optical properties of the samples were also investigated. XRD analysis of naked CoFe 2 O 4 revealed cubic spinel crystal structure. XRD patterns of CoFe 2 O 4 samples supported with ODA-MNT (2, 4 and 6 wt%) closely resembled that of naked CoFe 2 O 4 confirm the role of ODA-MNT as a supporting material. The value of crystallite size calculated by Williamson-Hall method were found to be 75, 82, 112 and 128 nm for 0, 2, 4 and 6 wt% of ODA-MNT supported compound respectively, indicating that ODA-MNT influences the crystallization process of CoFe 2 O 4 . SEM analysis showed that particle size and degree of agglomeration are influenced by ODA-MNT content. Raman spectroscopic analysis confirms the synthesis of ODA-MNT supported CoFe 2 O 4 composites with some sort of interaction between MNT sheets and CoFe 2 O 4 nanoparticles allowing some cationic redistribution between octahedral and tetrahedral sites of Co ferrite structure. Dielectric constants of CoFe2O4/ODA-MNT composites were lower in all observed frequency range than pure CoFe 2 O 4 . The value of dielectric constant was found to be 19.7 for bare Co ferrite and 5.4 for ODA-MNT (2 wt%) supported CoFe 2 O 4 , which is 3.64 times lower than the value obtained in pure compound at 10 kHz. The value of band gap obtained for pure CoFe 2 O 4 was 1.53 eV. The band gap was found to be lower for CoFe 2 O 4 /ODA-MNT (2, 4 wt%) compounds. • An organoclay (ODA-MMT) supported CoFe 2 O 4 Nano-composites were synthesized using sol-gel autocombustion method. • The crystallite size of CoFe 2 O 4 /ODA-MMT composites (82–128 nm) was significantly larger than that of bare CoFe 2 O 4 (75 nm). • The dielectric constant of CoFe 2 O 4 /ODA-MMT (2 wt%) composite was 5.4, much lower than that of pure CoFe 2 O 4 (19). • The optical band gap of CoFe 2 O 4 /ODA-MMT (2 wt%) composite was 1.45 eV, lower than that of pure CoFe 2 O 4 (1.53 eV).