Consequences of Magnetic Interaction Phenomena in Granular Systems

Effect of γ-Fe2O3 Nanoparticles on the Cross-Linking and Final Properties of PVA/Citric Acid-Based Nanocomposites

“…It has to be noted that the maximum of M ZFC ( T ) shifts to higher temperatures (from 155 to 205 K, as marked in Figure ) when nanoparticle concentration increases. This correlation can be explained by dipolar interactions between single domain particles, which are very sensitive to the interparticle distance, as largely explained in the literature. , In our case, concentration increase brings particles closer to each other in average, reinforcing dipolar interactions between them. In the case of the 1NP-PVAxCA nanocomposite (Figure D), the paramagnetic background, possibly originated from CA byproducts, strongly overcomes the magnetic contribution of nanoparticles, mostly hindering the superparamagnetic effect in a similar way as was observed in the M versus H loop at 5 K.…”

Synthesis process, size and composition effects of spherical Fe3O4 and FeO@Fe3O4 core/shell nanoparticles

“…The magnetization temperature dependence of the studied samples was recorded in the zero-field-cooling (ZFC) and field-cooling (FC) modes with an applied magnetic field set to 100 Oe. As it can be seen in figure 4, clear differences in the magnetic response of the samples were measured, which can be linked to structural dissimilarities between the nanoparticles systems 2,34 .…”

“…These peaks are clearly distinguished and their values change from one sample to another, being T MAX ൎ 100 K and 45 K for samples S3 and S6, respectively. Such temperature is related to the so-called blocking temperature (T B ), which identifies the temperature of the transition between the blocked and the superparamagnetic regimes 2,34,35 . Comparable ZFC maximum values have been reported for Fe 3 O 4 diluted nanoparticles of nearly similar size 15,31 .…”

Structural analysis of magnetic nanocomposites based on chitosan

“…Moreover, ZFC and FC joint near to 300 K, which indicates that both blocking and irreversibility temperatures are probably close to room temperature. These are characteristics for highly or moderate interacting nanoparticulated systems, with a broad size distribution and where not all the NPs become unblocked at 300 K[66].…”