Low-temperature sol–gel synthesis of magnetite superparamagnetic nanoparticles: Influence of heat treatment and citrate–nitrate equivalence ratio

Magnetic Mesoporous Silica for Targeted Drug Delivery of Chloroquine: Synthesis, Characterization, and In Vitro Evaluation

“…Superparamagnetism can when the grain size is so small that only single magnetic domains are supported in grain [35] and superparamagnetic iron oxide nanoparticles are well known in the l ture under the acronym SPION [36]. The subspectra attributed to SPIONs were according to a previously reported approach [37,38] interpreting the magenta sub trum (Figure 2a,b) as a size-induced paramagnetic doublet due to Fe atoms in tetrah The most striking feature of the Mössbauer results, however, is the presence of asymmetric central doublets in the spectra, which are attributed to a superparamagnetic contribution of magnetite/maghemite nanoparticles. Superparamagnetism can occur when the grain size is so small that only single magnetic domains are supported in each grain [35] and superparamagnetic iron oxide nanoparticles are well known in the literature under the acronym SPION [36].…”

“…Superparamagnetism can occur when the grain size is so small that only single magnetic domains are supported in each grain [ 35 ] and superparamagnetic iron oxide nanoparticles are well known in the literature under the acronym SPION [ 36 ]. The subspectra attributed to SPIONs were fitted according to a previously reported approach [ 37 , 38 ] interpreting the magenta subspectrum ( Figure 2 a,b) as a size-induced paramagnetic doublet due to Fe atoms in tetrahedral sites (SPION-T) and the cyan subspectrum as a size-induced paramagnetic doublet due to Fe atoms in octahedral sites (SPION-O). It has to be noted that octahedral and tetrahedral sites are present in magnetite and maghemite structures; therefore, this analysis can conclude only the presence of nanoparticles, but not on the fraction of nanoparticles of each of these phases.…”