Influence of pH on the structural and magnetic properties of Fe-doped ZnO nanoparticles synthesized by sol gel method

In the present work, the influence of pH on the microstructure and magnetic properties of pure and doped ZnO nanoparticles with Fe is reported. Specifically, we synthesize nanoparticles using the sol gel method with pH = 3, 6 and 9. For pure ZnO it is verified that the lattice constants, crystallite size, lattice strain, dislocation density (δ) and crystallinity are affected with increasing the pH value. This result is decisive in the magnetic properties of the nanoparticles because the structural defects are responsible for an additional paramagnetism in addition to the typical diamagnetism of the pure material. For samples doped with 2% of Fe, was observed that there are also modifications in the microstructure as the pH increases and the value of the saturation moment per unit mass changes by 15%. That is attributed to the effect of pH on the structure of Fe-doped ZnO nanoparticles. This work contributes to the understanding the effects of pH on the magnetic properties of pure and doped ZnO nanoparticles with transition metals. [Display omitted] •Pure and Fe-doped ZnO nanoparticles were synthesized by the sol gel method•The structural and magnetic properties are dependent of the pH value•ZnO samples show paramagnetism in combination with typical diamagnetism