Abstract:There are extensive potential applications for small size and uniformly monodispersed MnFe2O4 nanoparticles in the fields of biological materials, stealth technology, magnetic liquid, lithium battery, etc. In this paper, uniformly monodispered MnFe2O4 magnetic nanoparticles were synthesized by using the poloy mixed hydrothermal method, which uses manganese chloride (MnCI2·6H2O) and iron nitrate (Fe(NO)3·6H2O) as the raw material, sodium hydroxide (NaOH) as the mineralizing agent, and TREG as the dispersant. Size controllable synthesis was achieved by controlling the reaction time. The properties of magnetic nanoparticles were tested by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), etc. Experimental results show that TREG has dispersion effect on MnFe2O4 magnetic nanoparticles and with the decreasing of particle size, its magnetization and coercivity decrease, band gap increases, and light absorption ability enhances. When the particle size is 5nm, unique absorption decline appears.