Takeshi Yanagida

Electrically driven resistance change in metal oxides opens up an interdisciplinary research field for next-generation non-volatile memory. Resistive switching exhibits an electrical polarity dependent "bipolar-switching" and a polarity independent "unipolar-switching", however tailoring the electrical polarity has been a challenging issue. Here we demonstrate a scaling effect on the emergence of the electrical polarity by examining the resistive switching behaviors of Pt/oxide/Pt junctions over

In nanowire growth using vapor-liquid-solid (VLS) mechanism, controlling catalyst diffusion has been a key issue since VLS growth is essentially no longer feasible in the absence of catalyst on the tip. Here the authors demonstrate the controllability of catalyst diffusion on MgO nanowire growth by ambient pressure and discuss the underlying physical mechanism. Drastic enhancement of oxide nanowire growth was found when increasing the ambient pressure under oxygen atmosphere, and surprisingly ev

The size controllability of oxide nanowires formed via vapor-liquid-solid (VLS) mechanism is desired for the oxide nanowire-based device applications. However, the complex nature of oxide nanowire VLS growth has held back such size controllability. Here we demonstrate the critical size effect of a Au catalyst on MgO nanowire VLS growth by pulsed laser deposition. The presence of a critical catalyst size was found. Above such critical size, an oxide nanowire VLS growth is no longer feasible. Inte

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical features allow the integrated sensor electronics to work with a long-term stability, ultra-low power consumption, and miniature device size, which prom

The nature of metal-insulator transition and ferromagnetism phenomena of perovskite ${\mathrm{La}}_{0.7}{\mathrm{Ce}}_{0.3}{\mathrm{MnO}}_{3}$ thin films was investigated. In particular, the effects of post-annealing under oxidization and reduction atmospheres on the electrical transport and magnetic properties were systematically examined. The metal-insulator transition temperature and the Curie temperature of ferromagnetism were found to be significantly influenced by the post-annealing and in

Oxide nanowires formed via the vapor−liquid−solid (VLS) mechanism are potential candidates to incorporate the rich functionalities into the nanowire-based devices. However, the complex nature of oxide VLS mechanism has held back the formation of well-defined oxide nanowires. Here we report the enhancement of oxide VLS growth by carbon and discuss the underlying mechanism. In ZnO nanowire growth, the presence of carbon layers predeposited on the substrate surface strongly enhances the VLS growth.