Matrix effects on the magnetic properties of γ-Fe2O3 nanoparticles dispersed in a multiblock copolymer

Abstract

The magnetic properties of γ-Fe2O3 ferrimagnetic nanoparticles embedded in a multiblock poly(ether-ester) copolymer have been investigated by static magnetization and ferromagnetic resonance (FMR) measurements at two different dispersion states. Significant variation of the magnetic response is identified below T≈120K, most pronounced in the marked resonance field shift of the FMR spectra, independently of the dispersion state of the nanocomposites. This behavior correlates favorably with the dynamic relaxation of the copolymer, indicating a matrix freezing effect that is attributed to the magnetoelastic coupling of the oxide nanoparticles with the surrounding polymer. At low temperatures, the dc magnetization and FMR measurements vary considerably for the two nanocomposites, indicating essential differences in their ground state, related to the different morphology of the samples and the concomitant variation of interparticle interactions.

Magnetic studies of 0.7(Fe2O3)/0.3(ZnO) nanocomposites in nanopowder form and dispersed in polymer matrix

“…Exactly the same behavior was seen in our 0.7(Fe 2 O 3 )/0.3(ZnO) nanopowder sample in which strong interparticle interactions have been expected. The magnetization M(H) of large aggregates was smaller than that of separate nanoparticles and exhibited a relatively slower increment at low fields in the study of maghemite samples [16]. This was also confirmed in our study of 0.7(Fe 2 O 3 )/0.3(ZnO) nanopowder and polymer samples.…”

“…This was also confirmed in our study of 0.7(Fe 2 O 3 )/0.3(ZnO) nanopowder and polymer samples. As the hysteresis loop is concerned the coercive field was bigger for the sample containing agglomerated maghemite nanoparticles than for the dispersed ones [16]. In case of our 0.7(Fe 2 O 3 )/0.3(ZnO) samples a reversed effect was registered: the coercive field was bigger for the polymer sample.…”

“…Matrix effects on magnetic properties of γ-Fe 2 O 3 (maghemite) nanoparticles dispersed in a multiblock copolymer have been investigated previously [16]. Behavior of two polymer samples with magnetic nanoparticles in two different dispersion forms (large agglomerates and separate nanoparticles) was compared.…”

Thermal Effects on the Ferromagnetic Resonance in Polymer Composites with Magnetic Nanoparticles Fillers

“…As a particular example, we consider the FMR experiment with the γ-Fe 2 O 3 (maghemite) ferrimagnetic nanoparticles embedded in a multiblock poly(ether-ester) copolymer nonmagnetic matrix which has been studied both experimentally (Guskos et al, 2006; and theoretically (Dudek et al, 2010). However, the obtained results are general and applicable to other nanoparticles and other viscous materials.…”

Preparation and Characterizations of Iron Oxide Nano Particles Reinforced Polymeric Thin Films

“…Thus, the particles are being potentially used in photonics, electronics, biomedical, magnetically tunable materials, micro and nanofluidics, magnetic particle imaging, data storage and sensors [6,7]. In particular, iron oxide (Fe 2 O 3 ) nano-particles (IONPs) are widely used such applications due to their biocompatible and biodegradable nature and they can be easily controllable by magnetic field [8,9]. Further, the IONPs have very large surfaceto-volume ratio, thus they possess high surface energies [5].…”