Electrical transport properties of Ni80Fe20/HCl-PANI composites

• Ni80Fe20 films were sputter-deposited on HCl-PANI substrates.
• Ni80Fe20/HCl-PANI composites were obtained.
• The resistance-temperature behavior of composites is complicated.
• The interface layer influences the electrical property of the composite.

Ni80Fe20 films with a thickness of 40–170 nm were sputter-deposited on HCl-doped polyaniline (HCl-PANI) substrates at 300 K, forming the Ni80Fe20/HCl-PANI composites. In order to study the electrical transport property of the composite, a temperature dependence of the resistance (R–T) within 2–290 K was measured from the film surface and from the substrate back surface, respectively. The R–T curve measured from the film surface is very different from that measured from the substrate back surface. With the increase of temperature, the former exhibits the transition from almost temperature-independent region to semiconducting region whereas the latter shows a decrease of resistance. The transition temperature increases with increasing film thickness. The composite shows the temperature-independent feature below the transition temperature and the semiconducting feature over the transition temperature. Furthermore, for the R–T curve measured from the substrate back surface, the resistance of the composite is smaller than that of the HCl-PANI. With the increase of film thickness, it decreases and trends to be stable. The interface layer between the film and the substrate plays an important role in the electrical property of the composite.