EIMER GRISELDA ALEJANDRA
Artículos
Título:
Magnetic behavior of iron modified MCM-41 correlated with clustering processes from the wet impregnation method.
Autor/es:
NATALIA I. CUELLO; VERÓNICA R. ELÍAS; ELIN WINKLER; GABRIELA POZO LÓPEZ; MARCOS I. OLIVA; GRISELDA A. EIMER
Revista:
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2016 vol. 407 p. 299 - 299
ISSN:
0304-8853
Resumen:
agnetic MCM-41 type mesoporous silica materials were synthetized and modified with different iron loadings by the wet impregnation method. The evolution of speciation of iron, depending on the metal loading and associated with a particular magnetic behavior was investigated by M vs H curves, FC-ZFC curves, EPR spectroscopy and other complementary techniques such as SEM, TEM and chemisorption of pyridine followed by FT-IR studies. A superparamagnetic contribution was more notorious for the lower loadings suggesting the high dispersion of very small sized iron nanospecies. However, this contribution decreased with increasing metal loading due to the growing of magnetically blocked nanoparticles (hematite) on the outer surface. Finally, a bimodal size distribution for the superparamagnetic nanoespecies could be inferred; then the anisotropy constant for this phase and the corresponding nanoespecies sizes were estimated.