Synthesis and magnetic characterization of magnetite particles embedded in mesoporous MCM-41

• Published in: Journal of magnetism and magnetic materials Vol. 306; no. 1; pp. 30 - 34
• Main Authors: Fellenz, Nicolás A., Marchetti, Sergio G., Bengoa, José F., Mercader, Roberto C., Stewart, Silvana J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2006; Elsevier Science
• Subjects: Chemical synthesis; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diamagnetism, paramagnetism and superparamagnetism; Exact sciences and technology; Fe 3O 4; Magnetic nanoarrays synthesis; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Magnetically ordered materials; MCM-41; Mössbauer effect; other γ-ray spectroscopy; Nanofabrications; Nanoparticles magnetism; Nanostructures; Physics; Silylated MCM-41; 75.60.Ej; Nanofabrications; Magnetically ordered materials; Silylated MCM-41; 75.50.Tt; Fe 3O 4; Nanostructures; Magnetic nanoarrays synthesis; MCM-41; Nanoparticles magnetism; Chemical synthesis; 75.30.Cr; Moessbauer effect; Porous materials; Paramagnetism; Verwey transition; Superparamagnetism; Mesoporosity; Nanoparticles; Fe3O4; Magnetite; Composite materials; Iron oxides
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2006.02.101

A solid of 7.7 wt% iron-loaded MCM-41 was obtained by impregnating the mesoporous material with an Fe-carrying organic salt after subjecting the matrix to a silylation treatment. The Mössbauer and magnetic results show that the as-prepared composite is mainly made up of fine Fe 3O 4 particles that display a superparamagnetic relaxation at room temperature and block at ≈42 K. A percentage of ≈24% of the iron-containing phases is magnetically blocked at room temperature, and belongs to Fe 3O 4 that undergoes the Verwey transition. In addition, there is a minor Fe(III) phase that remains paramagnetic down to 4.2 K.