We have successfully controlled the size of magnetic nanoparticles by adjusting the surfactant/solvent ratio. γ-Fe 2O 3 nanoparticles of 5.6 and 12.7, and Fe 0 nanoparticles of 22.3 nm in diameter were prepared, all having spherical shape and uniform size as confirmed by TEM. Mössbauer spectra confirmed Fe 3+ for the 5.6 and 12.7 nm particles and Fe 3+ and Fe 0 for 22.3 nm particles, in good agreement with synchrotron XRD patterns. Both room temperature and 5 K H-M measurements show that 22.3 nm particles have much higher magnetization than their oxide counterparts, in agreement with their being Fe 0. T-M measurements show superparamagnetism for 5.6 and 12.7 nm particles and ferromagnetism for 22.3 nm particles.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry