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Matrix effects in magnetic resonance spectra of maghemite nanoparticles embedded in PTT-b-PTMO and PEN-b-PTMO matrices

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Matrix effects in magnetic resonance spectra of maghemite nanoparticles embedded in PTT-b-PTMO and PEN-b-PTMO matrices
Guskos, N. Maryniak, M. Zolnierkiewicz, G. Typek, J. Guskos, A. Senderek, E. Roslaniec, Z. Petridis, D.
scientific_publication_article
Επιστημονική δημοσίευση - Άρθρο Περιοδικού (EL)
Scientific publication - Journal Article (EN)
2008
Two samples containing γ-Fe 2O 3 (maghemite) magnetic nanoparticles homogenously dispersed at a concentration of 0.1% in two different polymer matrices, poly(ether-ester) multiblock copolymers of poly(trimethylene terephthalate)-block-poly(tetramethylene oxide) (PTT-b-PTMO) and poly(ethylene naphthalate)-block-poly(tetramethylene oxide) (PEN-b-PTMO), have been prepared. The polymer filler was in the form of suspension containing magnetic nanoparticles arranged in agglomerates with a size of less than 100 nm. The samples have been characterized by X-ray diffraction spectroscopy and scanning electron microscopy. The magnetic resonance measurements have been carried out in the 3.2-300 K temperature range. An intense slightly asymmetric resonance absorption from γ-Fe 2O 3 has been recorded. The derivative spectra could be fitted by two Gaussian lines, including the resonance absorption at negative field. The resonance lines at 295 K were centered at H r(I) = 343.7(0.2) and 333.8(0.2) mT, H r(II) = 298.6(0.2) and 286.5(0.2) mT with line widths ΔH(I) = 37.5(0.1) and 37.1(0.1) mT, ΔH(II) = 30.1(0.1) and 25.9(0.1) mT for PTT-b-PTMO and PEN-b-PTMO polymers, respectively. The integrated intensities were almost the same for both samples, while the observed differences in resonance fields, intensities and line widths suggested that the magnetic interactions depended essentially on the matrix type. All ferromagnetic resonance spectra parameters have shown an anomalous behavior at critical points of the matrix. © 2008 Springer-Verlag. (EN)
English
https://creativecommons.org/licenses/by-nc/4.0/
University of Athens
Pergamos Digital Library
Journal Article



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