Magnetic characterization of Fe nanoparticles dispersed in phyllosilicate type silicon oxide

Abstract

We present the magnetic properties of silica-supported metal (Fe,catalyst) nanoparticles synthesized by precipitation of metal nitrate in ammonia-based medium. Our goal is the study of possible metal-support interactions in the nanoporous catalyst. The temperature dependence of the magnetization for all samples display spin-glass like behavior below c.a. 11-12 K, with clear Curie-Weiss dependence in the high-temperature regime. Spin-glass-like behavior was inferred from dynamic AC susceptibility data after analyzing the frequency-dependence of the in-phase component χ′(f) by the expression W = ΔTf/[Tf Δlog(f)] =3.0 × 10 -3. We found that the magnetic behavior of the catalyst is drastically affected by the existence of interactions between the metal and the support. © 2010 IOP Publishing Ltd.