Electrical and magnetic properties of polyaniline/Fe3O4 nanostructures

✍ Scribed by Yunze Long; Zhaojia Chen; Jean Luc Duvail; Zhiming Zhang; Meixiang Wan

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 786 KB
• Volume: 370
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.09.009

✦ Synopsis

We report on electrical and magnetic properties of polyaniline (PANI) nanotubes ($150 nm in diameter) and PANI/ Fe 3 O 4 nanowires ($140 nm in diameter) containing Fe 3 O 4 nanoparticles with a typical size of 12 nm. These systems were prepared by a template-free method. The conductivity of the nanostructures is 10 À1 -10 À2 S/cm; and the temperature dependent resistivity follows a ln r$T À1/2 law. The composites (6 and 20 wt% of Fe 3 O 4 ) show a large negative magnetoresistance compared with that of pure PANI nanotubes and a considerably lower saturated magnetization (M s ¼ 3.45 emu/g at 300 K and 4.21 emu/g at 4 K) compared with the values measured from bulk magnetite (M s ¼ 84 emu/g) and pure Fe 3 O 4 nanoparticles (M s ¼ 65 emu/g). AC magnetic susceptibility was also measured. It is found that the peak position of the AC susceptibility of the nanocomposites shifts to a higher temperature (4245 K) compared with that of pure Fe 3 O 4 nanoparticles (190-200 K). These results suggest that interactions between the polymer matrix and nanoparticles take place in these nanocomposites.