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

NICOLÁS A. FELLENZ; SERGIO G. MARCHETTI; JOSÉ F. BENGOA; ROBERTO C. MERCADER; SILVANA J. STEWART

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

Elsevier

Año: 2006 vol. 306 p. 30 - 34

0304-8853

A solid of 7.7wt% 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 Fe3O4 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 Fe3O4 that undergoes the Verwey transition. In addition, there is a minor Fe(III) phase that remains paramagnetic down to 4.2 K.