[en] The apparent field-effect-transistor (FET)-like operations of a device based on a network of single-walled carbon nanotubes (SWCNTs) are elucidated with the help of local probe electrical characterization methods using an atomic force microscope. The apparent switching behavior of the device with an on-off ratio>10⁴ is found to be due to just two localized areas in the network of SWCNTs based on the measurements by electrostatic force microscopy and scanning gate microscopy. The result demonstrates that the conductance of a network of SWCNTs can be dominated by localized perturbations.

[en] We observed bipolar switching behavior from an epitaxial strontium cobaltite film grown on a SrTiO₃ (001) substrate. The crystal structure of strontium cobaltite has been known to undergo topotactic phase transformation between two distinct phases: insulating brownmillerite (SrCoO_2.5) and conducting perovskite (SrCoO_3−δ) depending on the oxygen content. The current–voltage characteristics of the strontium cobaltite film showed that it could have a reversible insulator-to-metal transition triggered by electrical bias voltage. We propose that the resistance switching in the SrCoO_x thin film could be related to the topotactic phase transformation and the peculiar structure of SrCoO_2.5