The effects of temperature and reaction time on the formation of manganese ferrite nanoparticles synthesized by hydrothermal method

Abstract

In order to optimize the hydrothermally synthesized manganese ferrite nanoparticles, the nanoparticles were synthesized under different reaction conditions. The effects of reaction temperature and time were investigated in a wide range. The samples have additional phases (hematite, maghemite) at high temperatures, and the sample synthesized at 120 °C has two different types of nanoparticles. However, the pure manganese ferrite phase was obtained as the reaction time increased at 130 °C. Particle size increased from 16.1 ± 6.1 nm to 25.8 ± 7.4 nm and from 19.4 ± 8.4 nm to 25.8 ± 8.2 nm with the rise of reaction temperature and time, respectively. The saturation magnetization Ms of the nanoparticles also increased with the increase of reaction temperature and time. Although the Ms values and particle sizes are very close for the samples synthesized at high temperature (at 220 °C for 4 h) and long reaction time (16 h at 130 °C), pure phase of manganese ferrite with high Ms (65 emu/g) was observed at low temperature and long reaction time.