Abstract
(Di)electric properties of MnZn ferrite particles coated by conductive (emeraldine salt) and non-conductive (emeraldine base) forms of PANi were measured and discussed in relation to properties of individual components of such composite. The electric response in a wide frequency (0.1 Hz–10 MHz) and temperature (−150 to 100 °C) range was determined. Recorded relaxation processes were identified as a result of hopping charge carriers, which either only polarize or give rise to DC conductivity. Temperature dependence of conductivity modelled by variable range hopping model indicated different system dimensionality: 3D in PANi bulk and 1D in PANi film, that is result of PANi morphology variation. AC conductivity frequency spectra were well approximated by power law model, and temperature evolution of its exponent was related to the type of charge involved in the charge transport. Altogether, the overlayer of conductive PANi increases by two orders of magnitude the electrical conductivity of ferrite/PANi composite compared to pristine ferrite, whereas non-conductive PANi reduced it by three orders of magnitude. Therefore, the electrical properties of ferrite/PANi composites are determined by electrical properties of PANi, which in turn depend upon mesoscale charge transport in PANi.
Published Version
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