Magnetic and conducting properties of composites of conducting polymers and ferrite nanoparticles

MUÑOZ RESTA, I.; HORWITZ, G.; LANÚS MENDEZ ELIZALDE, M.; JORGE, G. A.; MOLINA, F. V.; ANTONEL, P. S.

Buenos Aires

Congreso; X Latin American Workshop on Magnetism, Magnetic Materials and their Applications; 2013

Magnetic nanomaterials have a high interest not only by their very important applications in data storage, but also due to the intrinsic interest on the magnetic properties in the nanoscale. The use of conducting polymers gives rise to materials with both high magnetic susceptibilities and high conductivity. In this work, composites of ferromagnetic CoFe2O4 nanoparticles and two different conducting polymers (polypyrrole -Ppy- and polyethylenedioxythiophene -PEDOT-) were prepared and characterized. For both polymers, the synthesis was performed by the polymerization of the monomer in presence of a dispersion of the magnetic nanoparticles, in dierent CoFe2O4-monomer ratios. In the case of PEDOT-composites, DBSA (dodecylbenzensulfonic acid) was used as protecting agent and acid media. For CoFe2O4-PPy composites it was found that the nanoparticles size decreases (in the same way for all the studied ratios) during the polymerization process. On the other hand, for CoFe2O4-PEDOT composites, the nanoparticles remain intact during the polymerization, due to the presence of DBSA. For PPy-composites, both the coercive field and the applied eld required to reach the magnetization of saturation decrease as the polymer content in the composite increases. For PEDOT-composites, the remanence ratio increases as the polymer content increases, indicating the presence of interactions related to the amount of polymer present. This result suggests the presence of magnetic interactions between the magnetic nanoparticles and the polymer matrix. Moreover, the type of interaction seems to be different, depending on the polymer identity. Also the electrical conductivity was measured for all the prepared composites. For both PPy and PEDOT composites, those with high polymer content show electrical conductivity, observing a decrease in this magnitude as the polymer content in the composite decreases. In conclusion, the magnetic properties of CoFe2O4 nanoparticles can be modulated not only by varying the polymer identity but also by preparing composites with different CoFe2O4-polymer ratios.