Resistive-Switching Memory Effects of NiO Nanowire/Metal Junctions

Oka, Keisuke,Yanagida, Takeshi,Nagashima, Kazuki,Kawai, Tomoji,Kim, Jin-Soo,Park, Bae Ho American Chemical Society 2010 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.132 No.19

<P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2010/jacsat.2010.132.issue-19/ja101742f/production/images/medium/ja-2010-01742f_0003.gif'> <P>We have demonstrated the construction of highly stable resistive switching (RS) junctions with a metal/NiO nanowire/metal structure and used them to elucidate the crucial role of redox events in the nanoscale bipolar RS. The presented approaches utilizing oxide nanowire/metal junctions offer an important system and platform for investigating nanoscale RS mechanisms of various oxide materials.</P></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja101742f'>ACS Electronic Supporting Info</A></P>

Resistive Switching Multistate Nonvolatile Memory Effects in a Single Cobalt Oxide Nanowire

Nagashima, Kazuki,Yanagida, Takeshi,Oka, Keisuke,Taniguchi, Masateru,Kawai, Tomoji,Kim, Jin-Soo,Park, Bae Ho American Chemical Society 2010 NANO LETTERS Vol.10 No.4

<P>A multistate nonvolatile memory operated at sublithographic scale has been strongly desired since other nonvolatile memories have confronted the fundamental size limits owing to their working principles. Resistive switching (RS) in metal−oxide−metal junctions, so-called ReRAM, is promising for next generation high-density nonvolatile memory. Self-assembled oxide nanowire-based RS offers an attractive solution not only to reduce the device size beyond the limitation of current lithographic length scales but also to extract the underlying nanoscale RS mechanisms. Here we demonstrate the multistate bipolar RS of a single Co<SUB>3</SUB>O<SUB>4</SUB> nanowire (10 nm scale) with the endurance up to 10<SUP>8</SUP>. In addition, we succeeded to extract a voltage-induced nanoscale RS mechanism rather than current-induced RS. These findings would open up opportunities to explore not only for the intrinsic nanoscale RS mechanisms with the ultimate size limit but also for next generation multistate three-dimensional ReRAM.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2010/nalefd.2010.10.issue-4/nl9042906/production/images/medium/nl-2009-042906_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl9042906'>ACS Electronic Supporting Info</A></P>

Prominent Thermodynamical Interaction with Surroundings on Nanoscale Memristive Switching of Metal Oxides

Nagashima, Kazuki,Yanagida, Takeshi,Oka, Keisuke,Kanai, Masaki,Klamchuen, Annop,Rahong, Sakon,Meng, Gang,Horprathum, Mati,Xu, Bo,Zhuge, Fuwei,He, Yong,Park, Bae Ho,Kawai, Tomoji American Chemical Society 2012 NANO LETTERS Vol.12 No.11

<P>This study demonstrates the effect of surroundings on a memristive switching at nanoscale by utilizing an open top planar-type device. NiO<SUB><I>x</I></SUB> and CoO<SUB><I>x</I></SUB> planar-type devices have exhibited a memristive behavior under atmospheric pressure, whereas TiO<SUB>2-<I>x</I></SUB> planar-type devices did not show a memristive switching even under the same surroundings. A memristive behavior of TiO<SUB>2-<I>x</I></SUB> planar-type devices has emerged when reducing an ambient pressure and/or employing a SiO<SUB>2</SUB> passivation layer. These results reveal that a thermodynamical interaction with surroundings critically determines the occurrence of memristive switching via varying a stability of nonstoichiometry. Since this effect tends to be more significant for smaller devices with larger specific surface area, tailoring the surrounding effect by an appropriate passivation will be essential for high density devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-11/nl302880a/production/images/medium/nl-2012-02880a_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl302880a'>ACS Electronic Supporting Info</A></P>

Intrinsic Mechanisms of Memristive Switching

Nagashima, Kazuki,Yanagida, Takeshi,Oka, Keisuke,Kanai, Masaki,Klamchuen, Annop,Kim, Jin-Soo,Park, Bae Ho,Kawai, Tomoji American Chemical Society 2011 Nano letters Vol.11 No.5

<P>Resistive switching (RS) memory effect in metal-oxide-metal junctions is a fascinating phenomenon toward next-generation universal nonvolatile memories. However the lack of understanding the electrical nature of RS has held back the applications. Here we demonstrate the electrical nature of bipolar RS in cobalt oxides, such as the conduction mechanism and the switching location, by utilizing a planar single oxide nanowire device. Experiments utilizing field effect devices and multiprobe measurements have shown that the nanoscale RS in cobalt oxides originates from redox events near the cathode with p-type conduction paths, which is in contrast with the prevailing oxygen vacancy based model.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2011/nalefd.2011.11.issue-5/nl200707n/production/images/medium/nl-2011-00707n_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl200707n'>ACS Electronic Supporting Info</A></P>

Spatial Nonuniformity in Resistive-Switching Memory Effects of NiO

Oka, Keisuke,Yanagida, Takeshi,Nagashima, Kazuki,Kanai, Masaki,Kawai, Tomoji,Kim, Jin-Soo,Park, Bae Ho American Chemical Society 2011 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.133 No.32

<P>Electrically driven resistance change phenomenon in metal/NiO/metal junctions, so-called resistive switching (RS), is a candidate for next-generation universal nonvolatile memories. However, the knowledge as to RS mechanisms is unfortunately far from comprehensive, especially the spatial switching location, which is crucial information to design reliable devices. In this communication, we demonstrate the identification of the spatial switching location of bipolar RS by introducing asymmetrically passivated planar NiO nanowire junctions. We have successfully identified that the bipolar RS in NiO occurs near the cathode rather than the anode. This trend can be interpreted in terms of an electrochemical redox model based on ion migration and p-type conduction.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2011/jacsat.2011.133.issue-32/ja206063m/production/images/medium/ja-2011-06063m_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja206063m'>ACS Electronic Supporting Info</A></P>

Inhibition of ENNG-Induced Pyloric Stomach and Small Intestinal Carcinogenesis in Mice by High Temperature- and Pressure-Treated Garlic

Kaneko, Takaaki,Shimpo, Kan,Chihara, Takeshi,Beppu, Hidehiko,Tomatsu, Akiko,Shinzato, Masanori,Yanagida, Takamasa,Ieike, Tsutomu,Sonoda, Shigeru,Futamura, Akihiko,Ito, Akihiro,Higashiguchi, Takashi Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

High temperature- and pressure-treated garlic (HTPG) has been shown to have enhanced antioxidative activity and polyphenol contents. Previously, we reported that HTPG inhibited 1,2-dimethylhydrazine-induced mucin depleted foci (premalignant lesions) and $O^6$-methylguanine DNA adduct formation in the rat colorectum. In the present study, we investigated the modifying effects of HTPG on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG)-induced pyloric stomach and small intestinal carcinogenesis in mice. Male C57BL/6 mice were given ENNG (100 mg/l) in drinking water for the first 4 weeks, then a basal diet or diet containing 2% or 5% HTPG for 30 weeks. The incidence and multiplicity of pyloric stomach and small intestinal (duodenal and jejunal) tumors in the 2% HTPG group (but not in the 5% HTPG group) were significantly lower than those in the control group. Cell proliferation of normal-appearing duodenal mucosa was assessed by MIB-5 immunohistochemistry and shown to be significantly lower with 2% HTPG (but again not 5% HTPG) than in controls. These results in dicate that HTPG, at 2% in the diet, inhibited ENNG-induced pyloric stomach and small intestinal (especially duodenal) tumorigenesis in mice, associated with suppression of cell proliferation.

Size control of magnetite nanoparticles in hydrothermal synthesis by coexistence of lactate and sulfate ions

Naoya Mizutani,Tomohiro Iwasaki,Satoru Watano,Takeshi Yanagida,Tomoji Kawai 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The size of magnetite nanoparticles was controlled by means of coexistence effects of anions in the starting solution of organic solvent-free hydrothermal synthesis via coprecipitation. As the coexisting anions,lactate ion, which forms relatively stable complex with ferric ion, and sulfate ion were used. The hydrothermal synthesis was carried out at various concentrations of lactate and sulfate ions. The obtained magnetite nanoparticles were characterized by a scanning electron microscope, transmission electron microscope, powder X-ray diffractometer, dynamic light scattering particle size analyzer and superconducting quantum interference device. The formation mechanism of magnetite nanoparticles in this system was investigated based on the experimental results. The coexisting anions remarkably influenced both formation of crystalline nuclei and dispersion stabilization of formed precipitates. The particle size depended strongly on the concentration of lactate and sulfate ions. It has been clarified that lactate ion has the effect to decrease the particle size and sulfate ion promotes the particle growth. By adjusting the concentration of lactate and sulfate ions properly as the operating factor, we could control successfully the particle size from 9.5 to 38.6 nm in median size.

Phase 2 single-arm study on the efficacy and safety of niraparib in Japanese patients with heavily pretreated, homologous recombination-deficient ovarian cancer

Aikou Okamoto,Eiji Kondo,Toshiaki Nakamura,Satoshi Yanagida,Junzo Hamanishi,Kenichi Harano,Kosei Hasegawa,Takeshi Hirasawa,Kensuke Hori,Shinichi Komiyama,Motoki Matsuura,Hidekatsu Nakai,Hiroko Nakamur 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.2

Objective: To evaluate the efficacy and safety of niraparib in Japanese women with heavilypretreated ovarian cancer. Methods: This Phase 2 open-label, single-arm study enrolled Japanese women withhomologous recombination deficiency-positive relapsed, high-grade serous ovarian,fallopian tube, or primary peritoneal cancer who had completed 3–4 lines of therapy. The starting dose of niraparib was 300 mg administered once daily in continuous 28-daycycles until objective progressive disease, unacceptable toxicity, consent withdrawal ordiscontinuation. The primary endpoint, objective response rate (ORR), was assessed bythe investigator using RECIST version 1.1. Safety evaluations included the incidence oftreatment-emergent adverse events (TEAEs), including serious TEAEs. Results: Twenty women were enrolled and the confirmed ORR in the full analysis set (FAS)was 35.0% (7/20), consisting of 1 complete response and 6 partial responses. Diseasecontrol rate in the FAS was 90.0%. The most frequently reported TEAEs (>50%) wereanemia, nausea, and platelet count decreased. One patient (5.0%) had TEAEs leadingto discontinuation of niraparib whereas reductions or interruptions were reported in 14(70.0%) and 15 (75.0%) patients, respectively. The median dose intensity (202.9 mg daily)corresponded to a relative dose intensity of 67.6%. Conclusion: Efficacy and safety of niraparib in heavily pretreated Japanese women wascomparable to that seen in an equivalent population of non-Japanese women. No new safetysignals were identified.Trial Registration: ClinicalTrials.gov Identifier: NCT03759600