Magnetic and dielectric properties of ZnFe2O4/nanoclay composites synthesized via sol-gel autocombustion

Highlights: • ZnFe₂O₄/ODA-MMT was synthesized via autocombustion. • ZnFe₂O₄/ODA-MMT showed higher value of saturation magnetization than naked ZnFe₂O_4. • ZnFe₂O₄/ODA-MMT showed enhancement in dielectric constant over naked ZnFe₂O_4. • ODA-MMT influenced the crystallization and agglomeration of ZnFe₂O₄ nanoparticles. • Exfoliation of MMT layers into ZnFe₂O₄ particles are anticipated. The current research aims to systematically investigate the influence of octadecylalkylammonium intercalated montmorillonite (ODA-MMT) as supporting material on the crystallographic, morphological, magnetic and dielectric characteristics of Zn ferrite (ZnFe₂O₄) nanoparticles. There have been executed the synthesis of ZnFe₂O₄ samples through sol-gel auto-combustion method for a variety of ODA-MMT contents (0–6 wt% in step of 2). XRD, FESEM, FTIR techniques have been employed for the structural verification of naked and ODA-MMT supported ZnFe₂O₄, while the magnetic and dielectric behaviors have been examined meticulously. The XRD data are augmented by Scherrer method, W–H and W-A analysis to consolidate different microstructural parameters such as crystallite size, strain, dislocation density, etc. XRD measurement reveals the desired phases (cubic spinel phases) of ZnFe₂O₄. The incorporation of ODA-MMT as a supporting material in ZnFe₂O₄ leads to a decrement of crystallite size. The values of saturation magnetization are found to be in the range of 51.6–58.1 emu/g in ODA-MMT supported compounds which is much higher than the value of 41.6 emu/g found for 0 wt% ('naked') Zn ferrite. Dielectric constant enhanced significantly (~165% in 4 wt% ODA-MMT supported compound) when ODA-MMT is used as a supporting material for Zn ferrite nanoparticles. Enhancement of dielectric constant in ODA-MMT supported Zn ferrite is appeared to be related with the degree of exfoliation of montmorillonite layers into ZnFe₂O₄ particles.