Structural, dielectric and magnetic properties of (ZnFe2O4/Polystyrene) nanocomposites synthesized by micro-emuslion technique

This work aims to study the effect of polymer on the structure, magnetic and dielectric properties of spinel ferrite composite. Nanocomposites based on polystyrene (PST)/ZnFe2O4 were synthesized by using the micro-emulsion method. The novel composites with PST to ZnFe2O4 ratios (4:0, 4:1, 4:2, 4:3, 4:4, 0:4) were analyzed by X-ray diffractometer (XRD) which confirms the spinel structure of ZnFe2O4 with an average crystallite size of 15.3 nm for pure ZnFe2O4 and decreases by increasing the polystyrene concentration. Field Emission Scanning Electron Microscopy (FESEM) gave the optimized results of surface morphology and the crystallite size which are in accordance with XRD data. Fourier Transform Infrared (FTIR) spectra show two main broad metal-oxygen bands corresponding to the intrinsic stretching vibrations of the metal at the tetrahedral site (observed between 837.9 and 1034.3 cm(-1)) and traces of organic materials were observed at 1499.2 and 1766.4 cm(-1), which are associated with C=O and C=C stretching vibration respectively. O-H stretch of COOH weak acid of the carboxyl group was found at 2978.7 cm(-1) The composite with equal ZnFe2O4 to PST ratio (4:4) shows that real part of dielectric constant is independent of frequency at lower frequencies of an applied electric field. The resonance type behaviour was observed at higher frequency (2.5 GHz) which shows the material is excellent for dispersion of electric part of microwaves. The magnetization for pure ferrite (ZnFe2O4) at 15000 Oe was found to be 1.49 emu/g which decreases to 0.54 emu/g for the composite with the equal ferrite to polystyrene ratio. Based on their dielectric and magnetic characterization, these composites are considered suitable candidates to employ as microwave absorbing materials.