Fe-57 Mossbauer spectra study of coated alpha-Fe2O3 nanoparticles

Nano-sized alpha-Fe2O3 particles coated with polar organic molecules have been studied using the Mossbauer spectroscopy method. The alpha-Fe2O3 nanoparticles were prepared by the microemulsion method. The average particle size of the Fe2O3 particles is about 24 Angstrom. Because the particle size is so small that the Mossbauer spectra of the alpha-Fe2O3 samples only consist of a quadrupole-split central line. It was proved that the Isomer Shifts (DIS) and the Quadrupole Splitting (DQS) changed as the refluxing time prolongs and the refluxing temperature increases during the preparation of the Fe2O3 nanoparticles, which implied an enhancement of the surface electrofield gradient formed by the surface coated polar molecules during the refluxing process.