Bi-magnetic iron (III) oxide nanocrystals embedded in MCM-41 mesoporous silica

S. STEWART; A. F. CABRERA; N. FELLENZ; R. MERCADER; J. BENGOA; G. MARCHETTI

Conferencia; REunión Nacional de Sólidos; 2015

Bi-magnetic nanoparticles having an iron oxide (IONPs) as one (at least) of its constituents are attracting increasingly attention to develop systems able to retain or enhance the properties and functionalities of their individual counterparts for diverse applications [1-6]. For basic studies, the interest resides on whether the anomalous magnetic behaviors observed can be associated to surface effects due to the spin canting, to compositional gradients and defects in the interfacial region that connects two different and distinguishable phases [3] or due to size confinement [4]. We have employed the mesoporous silica sieve MCM-41 as a reservoir to confine IONPs composed by exchange-coupled hematite and maghemite-like species. They are embedded inside the MCM-41 nanochannels and arranged in a string of beads configuration. We present a detailed magnetic characterization of these confined bi-component IONPs through static and dynamic studies