The effect of basic pH on the elaboration of ZnFe2O4 nanoparticles by co-precipitation method: Structural, magnetic and hyperthermia characterization
Résumé
The present study reports on the synthesis and characterization of zinc iron oxide ZnFe2O4 magnetic nanoparticles (MNPs) using the co-precipitation method. Particular attention has been paid to study the influence of the pH in the range between 9 and 12 on both structural and magnetic properties of the MNPs. X-ray diffraction analysis shows the presence of a single phase of partially invers cubic spinel ferrites ZnFe2O4. Transmission Electron Microscopy (TEM) analysis shows the formation of highly crystalline MNPs and a change of shape from a polyhedral shape at pH 9 to a spherical-like shape for a pH 12. The MNPs mean-size increases from 19 to 33 nm with the increase of pH value. The ZnFe2O4 MNPs are superparamagnetic at room temperature displaying a magnetization of 12 emu/g at the maximum applied static magnetic field. The heating efficiency of spherical zinc ferrites MNPs was evaluated for hyperthermia application and displays a linear increment of the specific absorption rate (SAR) up to 125 (W/g(Fe)) under an alternating magnetic field ranging from 5 to 65 kA/m and operating at a frequency of 355 kHz.