Abstract

The typical perovskite manganite (La,Pr,Ca)MnO₃ shows exotic colossal magnetoresistivity which is associated to the insulator-metal transition (IMT) [1] from an insulator behavior at a high temperature to a metallic behavior at a low temperature through a critical transition temperature T_IM. Around T_IM, the phase-separated metal and insulator domains coexist in a nanometer scale. Since the conductive property in a phase-separated material is determined by the conductivity behaviors of metal/insulator nanodomains, understanding the electrical transport properties, i.e., quantitative evaluation of the change of metal fraction (X(T)) and the dc conductivity (σ_dc(T)) are required. Interestingly, owing to the confinement of nanodomains, the peculiar property was observed in a nanostructure [1], therefore the investigation of their electrical transport properties becomes extremely important. However this is still a challenging issue by using the electrical measurement with attached electrodes.

© 2015 Japan Society of Applied Physics, Optical Society of America