Magnetic resonance of magnetite nanoparticles dispersed in mesoporous copolymer matrix

Magnetic resonance is used to investigate fine particles of magnetite (Fe/sub 3/O/sub 4/) synthesized as isolated nanoparticles (INP's) in a mesoporous styrene-divinylbenzene (Sty-DVB) copolymer template. The magnetite nanoparticles were obtained through alkaline precipitation of ferrous sulfate, at different iron (II) concentration (Q), in the sulfonated polymeric matrix. Analysis of the temperature (T) dependence of the resonance field (H/sub R/) and resonance linewidth (/spl Delta/H/sub R/) provide a useful way to estimate the average size of the magnetite nanoparticles. The data indicates that the nanoparticle average diameter (D) increases as Q increases, in accordance with the data reported previously.