Structural, dielectric and magnetic properties of ZnFe2-xSrxO4 nanoparticles prepared by co-precipitation method

Strontium (Sr) substituted zinc ferrite (ZnFe2-xSrxO4) nanoparticles at x = 0.2, 0.4, 0.6 & 0.8 were prepared using simple and low cost co-precipitation method using polyethylene glycol as surfactant. From the X-ray diffraction (XRD) results, it was found that the prepared ZnFe2-xSrxO4 nanoparticles were crystallized in cubic spinel structure and the crystallite size decreases from 20 nm to 12 nm for x = 0.2 to x = 0.8. From optical studies it was found that the band gap of the ZnFe2-xSrxO4 nanoparticles increased (1.95 eV–2.13 eV) with increase of strontium concentration. The dielectric measurements show that the nanoparticles exhibited high dielectric constant at room temperature (30 °C) and low frequency (102 Hz) and it increased with strontium concentration. The magnetic properties of the zinc ferrite nanoparticles show ferromagnetic nature and the strength of magnetization increased with strontium concentration. •ZnFe2-xSrxO4 nano ferrites showed cubic spinel structure.•The crystallize size decreased by increasing the doping concentration and this was further confirmed by TEM micrographs.•The cubic structure of all nanoparticles were confirmed from HR-TEM and SAED patterns.•εr’ value increased with an increasing temperature and decreased slightly by increasing the Sr3+ concentration.•All the nanoparticles exhibited ferromagnetism at room temperature.