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- Resumen es exacto "Materials with both electrical and magnetic properties are required for various applications ranging from electric and magnetic shields, molecular electronics, sensors to microwave absorbers. Conducting polymers with the addition of magnetic oxides composites are suitable for such uses. Such is the case of the polyaniline (PANI), an organic polymer, mixed with magnetite. The conductive properties of this composite can be significantly improved by doping the polymer.
In this Thesis, a new chemical method is presented and composite samples of PANI/ Fe3O4 (nanoparticles) with different amount of magnetic oxide from 0,3% m/m on the composite up to 42% m/m are prepared. The final product is obtained in the powder form. The effect of different dopant acids on the PANI and its dissolution in different solvents are also analyzed. Furthermore, nanoparticles of magnetite are obtained at different temperatures. Structural morphological studies are performed on the oxides, on PANI and on the composite. For this purpose, XRD, IR spectroscopy, UV- Visible spectroscopy, microscopy and scanning and transmission Mössbauer spectroscopy, among other techniques, are employed. A structural model for the composite material is proposed. Transport properties are analyzed by measuring the electrical conductivity as a function of temperature, either in tablets or in films. The activation energy (Ea) for each system was calculated.
Magnetic characterization was performed on oxide samples and on the composite material through the hysteresis loops and FC- ZFC. The results are related to the particle size and to the influence of the percentage of oxide in the composite.
Finally, we study the behavior of these composites as absorbers of radiation in the microwave region to determine its potential technological application."
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