نتایج جستجو برای: essentially metallic oxides

تعداد نتایج: 118145  

2014
Michaela Kogler Eva-Maria Köck Lukas Perfler Thomas Bielz Michael Stöger-Pollach Walid Hetaba Marc Willinger Xing Huang Manfred Schuster Bernhard Klötzer Simon Penner

Carbon deposition following thermal methane decomposition under dry and steam reforming conditions has been studied on yttria-stabilized zirconia (YSZ), Y2O3, and ZrO2 by a range of different chemical, structural, and spectroscopic characterization techniques, including aberration-corrected electron microscopy, Raman spectroscopy, electric impedance spectroscopy, and volumetric adsorption techn...

2006
S. Terashima H. K. D. H. Bhadeshia

The trend in strong weld metals is towards microstructures dominated by low carbon martensite. The role of oxide particles introduced into the metal during welding then becomes uncertain. The particles do not seem to affect the nucleation or growth of martensite. This is probably because this phase forms at relatively large driving forces and therefore does not rely on heterogeneous nucleation ...

Journal: :Nature materials 2007
Rainer Waser Masakazu Aono

Many metal-insulator-metal systems show electrically induced resistive switching effects and have therefore been proposed as the basis for future non-volatile memories. They combine the advantages of Flash and DRAM (dynamic random access memories) while avoiding their drawbacks, and they might be highly scalable. Here we propose a coarse-grained classification into primarily thermal, electrical...

2007
Naoto Nagaosa Shuichi Murakami Hyun Cheol Lee

The interplay between the electron repulsion U and the Jahn-Teller electron-phonon interation E LR is studied with a large d model for the ferromag-netic state of the manganese oxides. These two interactions collaborate to induce the local isospin (orbital) moments and reduce the bandwidth B. Especially the retardation eeect of the Jahn-Teller phonon with the frequency is eeective to reduce B, ...

2007
D. Shahrjerdi D. I. Garcia-Gutierrez S. K. Banerjee

In this letter, we have investigated the physical and electrical characteristics of atomic layer deposition of HfO2 on GaAs substrates. X-ray photoelectron spectroscopy XPS analysis revealed no significant reduction of arsenic oxides upon deposition of HfO2 on GaAs using tetrakis dimethyl-amino hafnium Hf NMe2 4 as the metallic precursor. However, XPS confirmed the absence of arsenic oxides at ...

2009
Nobuo Furukawa

The double-exchange model, which has been extensively studied in the context of colossal magneto-resistance in perovskite manganese oxides, is known to exhibit a ferromagnetic metallic state at low temperatures because of the interplay between localized moments and itinerant electrons through the Hund’s-rule coupling. Here we investigate numerically the ferromagnetic transition in the double-ex...

Journal: :Physical chemistry chemical physics : PCCP 2015
Guangbiao Zhang Yuanxu Wang Zhenxiang Cheng Yuli Yan Chengxiao Peng Chao Wang Shuai Dong

We have investigated the structural, electronic, and magnetic properties of A-site-ordered double-perovskite-structured oxides, AA'3B4O12 (A = Na, Ca, and La) with Mn and V at A' and B sites, respectively, using first-principle calculations based on the density functional theory. Our calculation results show that the antiferromagnetic phase is the ground state for all the compounds. By changing...

2009
Sylvie Rangan Eric Bersch Robert Allen Bartynski Eric Garfunkel Elio Vescovo

Valence-band and conduction-band edges of ultrathin oxides SiO2, HfO2, Hf0.7Si0.3O2, and Al2O3 grown on silicon and their shifts upon sequential metallization with ruthenium have been measured using synchrotronradiation-excited x-ray, ultraviolet, and inverse photoemissions. From these techniques, the offsets between the valence-band and conduction-band edges of the oxides, and the ruthenium me...

2015
Xiang Hu Zhicheng Zhong Gregory A. Fiete

While the theoretical and experimental study of topological phases of matter has experienced rapid growth over the last few years, there remain a relatively small number of material classes that have been experimentally shown to host these phases. Most of these materials contain bismuth, and none so far are oxides. In this work we make materials-specific predictions for topological phases using...

Journal: :Chimia 2010
Fabienne Gschwind Aurélien Crochet William Maudez Katharina M Fromm

Heterometallic oxides are used as materials in many applications, e.g. from ferroelectrics to superconductors. Making these compounds usually requires high temperatures and long reaction times. Molecular precursors may contribute to render their processing shorter and accessible at lower temperatures, thus cheaper in energy and time. In this review article, different approaches toward oxide mat...

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