Preparation of superparamagnetic ZnFe2O4 submicrospheres via a solvothermal method

Superparamagnetic Zinc ferrite submicropheres are firstly synthesized via a one-pot solvothermal approach at 200-215°C for 4-8 hours. ZnCl2, FeCl3 and NaAc are used as precursors with ethylene glycol solvent. The X-ray diffraction (XRD) data indicate that ZnFe2O4 nanoparticles with the grain size around 15±3 nm can be successfully synthesized via the one-pot method. The scanning/transmission electronic microscope (SEM/TEM) images further show the samples are submicrospheres self-assembled by nanoparticles with size about 375-500 nm changed with reaction conditions. Room-temperature vibration magnetic strength measurements (VMS) demonstrates the as-obtained ZnFe2O4 submicrospheres show prefect superparamagnetism, whose coercivity force and remanence are practically nil. The reaction temperature and time influence on the crystallinity, diameter, saturated magnetic intensity and morphology of the particles.