Triggering a Metal-insulator Transition in La_0:8 Sr_0:2 MnO₃ Nanoparticle-decorated Carbon Nanotubes

We have studied the magnetic and the electric properties of La_0:8Sr_0:2MnO₃ (LSMO) nanoparticle-decorated carbon nanotubes (CNTs). The magnetic susceptibility showed a para- magnetic - superparamagnetic phase transition at T_SP ~ 200 K with a blocking temperature of T_B ~ 120 K, which can be attributed to the LSMO nanoparticles. At T_SP, the charge transport taking place through the CNTs network showed a metal-insulator transition (MIT) characteristic of the LSMO nanoparticles, indicating a concomitant MIT in the CNTs triggered by the LSMO nanoparticles. In the metallic phase, the charge transport appears to be dominated by a 2D weak localization effect, which at temperatures below T_B was seen to be somewhat suppressed by the internal field. At temperatures below 50 K, a Kondo effect dominates the electric and the magnetic properties.