Electrical and magnetic properties of the composite pellets containing DBSA-doped polyaniline and Fe nanoparticles

DBSA-doped polyaniline powder (DBSA-PANI) was mixed with Fe nanoparticles to obtain the DBSA-PANI-Fe composite. Powder of the composite was compacted to the pellets to study the electrical property and magnetization characteristic by measuring the conductivity in 100-300 K and the magnetization curve at room temperature. The conductivity of the composite pellet is linearly decreased from 0.25 +/- 0.02 to 0.07 +/- 0.01 S/cm with increasing the Fe nanoparticle content from 0 to 70 wt.%. For the pellets containing the Fe nanoparticles less than 70 wt.%, the variation of conductivity with temperature reveals that the charge transport mechanism can be considered to be one-dimensional variable-range-hopping (1D-VRH). For the pellet with 70wt.%-Fe nanoparticles, however, the charge transport mechanism cannot be well understood in terms of the VRH model. All the DBSA-PANI-Fe composite pellets show a magnetic hysteresis loop and a hard magnetization characteristic. The saturation magnetization monotonously increases from 32 to 78 emu/g with increasing the Fe nanoparticle content from 30 to 70 wt.%. The saturation field and the coercivity are estimated to be about 5500 and 385 Oe, respectively, independent of the Fe nanoparticle content. (c) 2006 Elsevier B.V. All rights reserved.