The effect of manganite nanoparticle addition on the low field magnetoresistance of polyaniline
In this report, we studied the effect of the addition of manganite nanoparticles on the microstructure and magnetotransport properties of polyaniline polymers. We showed experimental results on the fractal dimension of the polyaniline–manganite nanocomposites by means of small angle X-ray scattering measurements. A decrease in the number of polarons is observed for the composite with a concentration of 20% manganite nanoparticles. On the other hand, for the same concentration, the presence of a low magnetic field increases the number of polarons, in relation to an enhancement of the negative low field magnetoresistance (LFMR). This enhancement was observed for a critical amount of manganite nanoparticle addition in the whole temperature regime analyzed, as envisaged from the low magnetic field dependence in the polyaniline polaron formation observed using confocal Raman spectroscopy at room temperature.