Low temperature processing and magnetic properties of zinc ferrite nanoparticles

• High purity single-phase zinc ferrite nanoparticles with favorable crystallinity are synthesized by the Pechini process.
• The effect of post annealing temperature on microstructure and magnetic properties is studied.
• The effect of precursor on microstructure and magnetic properties is studied.
• A structure–property correlation is established.

Zinc ferrite nanoparticles were successfully synthesized by Pechini process and the effect of the calcination temperature and precursors on microstructure was investigated in detail using XRD, FT-IR, SEM, and TEM techniques. The thermal behavior of polymeric intermediates was studied by STA (TG–DTG–DTA) thermograms. Magnetic properties were studied by VSM technique. Results indicated that nanocrystalline zinc ferrite particles with a single-phase spinel structure were obtained. The nanoparticles possessed a spherical morphology with a particle size of 18–62 nm depending on the calcination temperature and precursor where higher calcination temperatures resulted in larger particles. It was also found that larger particles formed when polyethylene glycol-1000 (PEG) is used as precursor, while using ethylene glycol (EG) leaded to a smaller particle size. Magnetic properties of the samples were found to be greatly affected by the average crystallite size. The saturation magnetization values increased from 0.72 to 7.21 emu/g when the calcination temperature was raised from 400 to 900 °C. At a constant calcination temperature, the samples prepared with EG showed lower magnetization than those prepared with PEG. Results also showed that the utilization of PEG precursor decreased the porosity content of polymeric intermediates, which caused a poor combustion with long duration resulting in residual organic impurities in the samples. We show that magnetic characteristics of zinc ferrite nanoparticles can be precisely tuned by changing the calcination temperature and the precursors, expanding the range of practical applications of this material.