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Magnetic investigations of titanium-doped gamma iron oxides dispersed in polymers

  1. Mircea Chipara1,*,
  2. Ioan Morjan2,
  3. Rodica Alexandrescu2,
  4. Jeffrey M. Zaleski1,
  5. Nicholas Remmes3,
  6. David V. Baxter3

Article first published online: 24 OCT 2005

DOI: 10.1002/polb.20645

Issue

Journal of Polymer Science Part B: Polymer Physics

Journal of Polymer Science Part B: Polymer Physics

Special Issue: The American Physical Society Division of Polymer Physics Special Issue

Volume 43, Issue 23, pages 3432–3437, 1 December 2005

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How to Cite

Chipara, M., Morjan, I., Alexandrescu, R., Zaleski, J. M., Remmes, N. and Baxter, D. V. (2005), Magnetic investigations of titanium-doped gamma iron oxides dispersed in polymers. J. Polym. Sci. B Polym. Phys., 43: 3432–3437. doi: 10.1002/polb.20645

Author Information

  1. 1

    Department of Chemistry, Indiana University, Bloomington, Indiana 47405

  2. 2

    National Institute for Lasers, Plasma, and Radiation Physics, Bucharest, Romania

  3. 3

    Department of Physics, Indiana University, Bloomington, Indiana 47404

*Department of Chemistry, Indiana University, Bloomington, Indiana 47405

Publication History

  1. Issue published online: 24 OCT 2005
  2. Article first published online: 24 OCT 2005
  3. Manuscript Accepted: 28 JUL 2005
  4. Manuscript Revised: 9 JUN 2005
  5. Manuscript Received: 1 MAY 2005

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Keywords:

  • block copolymers;
  • electron microscopy;
  • ESR/EPR;
  • magnetic properties;
  • nanoparticles

Abstract

The preparation and characterization of titanium-doped iron oxides–styrene isoprene styrene block copolymer composites is reported. The precursor, as-synthesized nanoparticles, contains akaganeite, maghemite, and titanium-doped maghemite. Hysteresis loops obtained by SQUID measurements revealed an exchange biased field assigned to the presence of akaganeite nanoparticles. It was found that the coercive field and the exchange bias field decreases as the temperature of the sample is increased. The temperature dependence of the magnetization revealed a blocking temperature of about 220 K. The ESR spectra in the temperature range 150 K to about 300 K are single broad resonance lines. It was observed that the resonance line position is strongly temperature dependent due to the combined action of the external and molecular magnetic fields. The decrease of the resonance line width as the temperature is increased is governed by the reorientation of the magnetization. Thermally activated movements of magnetic nanoparticles within the soft phase (polyisoprene) of the matrix may also contribute to resonance line narrowing. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3432–3437, 2005

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