Critical size effects on the magnetic resonance in Fe3O4 nanoparticles -: art. no. 114322

In this work, Fe3O4 nanoparticles with two distinct diameters of 10 and 2 nm are synthesized with different chemical methods in order to investigate the critical size effects on the magnetic resonance of Fe3O4 nanoparticles. Our results clearly demonstrate a difference in the dynamic behaviors of resonance field (H-r) and resonance linewidth between these two nanoparticles. Furthermore, the nonlinear temperature dependency of H-r in 2-nm Fe3O4 suggests that the surface anisotropy becomes dominating on the magnetodynamics of nanoparticles when the diameter of the nanoparticle is smaller than the critical size. (C) 2005 American Institute of Physics.