The influence of the finite thickness and structure, amorphous or crystalline, of Fe electrodes on the tunneling magnetoresistance (TMR) ratio is investigated by ab initio calculations in Fe/MgO/Fe tunnel junctions. An amorphous Fe layer in direct contact with the MgO barrier causes a low TMR ratio of only 44%. By inserting crystalline Fe monolayers between the barrier and the amorphous Fe the ...

New oxides of the (NdSr)n+1MO3n+1 (M = Co and Mn or Fe) series are reported. Compounds of composition NdSrCo0.75Fe0.25O4.10, NdSrCo0.75Mn0.25O4.08 and Nd0.5Sr1.5Co0.75Mn0.25O3.86 are the n = 1 members of the Ruddlesden-Popper homologous series (K2NiF4 structural type) as determined by X-ray diffraction and different transmission electron microscopy techniques. Their crystal structure consists o...

Rate data for electrochemical and homogeneous redox reactions involving R u , ~ + / ~ + , V,q3+/2+, Fe,q3+/2+, E u , ~ ~ + / ~ + , and Cr,2+/2+ redox couples (where "aq" represents aquo ligands) have been analyzed and compared by using the rate relations due to Marcus in order to ascertain how the kinetics of outer-sphere electron exchange are dependent upon the metal redox center. The work-cor...

Power output limitation is one of the main challenges that needs to be addressed for full-scale applications of the Microbial Fuel Cell (MFC) technology. Previous studies have examined electrochemical performance of different cathode electrodes including the development of novel iron based electrocatalysts, however the long-term investigation into continuously operating systems is rare. This wo...

thin film phthalocyanines(pc), incloding zinc, iron, and magnesium phthalocyani-nes, were prepared by vacuum deposition method. chronocoulometry was used to study the charge transfer reaction mechanism of ionic species through the thin films. the results obtained in chronocoulometric studies shows that the thin film phthalocyanines could operate via two mechanisms.the first mechanism metal pc t...

The rotating ring disk electrode method has been used to study O2 electroreduction with metal corroles. Catalysis begins at potentials that are 0.5-0.7 V more positive than the expected potential of the M(III/II) couple based on studies in non-aqueous solutions. The path of O2 reduction depends on the nature of the metal ion. Cobalt corroles promote O2 reduction to H2O2. Iron corroles catalyse ...

Metal oxidation is one of the spontaneous chemical reaction, which is hard to control. Most metals inevitably have at least a few layers of oxides on the surface in natural environment. Because of the large impact of metal oxidation on infrastructure and transportation, surface oxidation and its role on structure and property have attracted significant attentions on the fundamental aspects of o...

Brazing generally require cumbersome apparatus be it induction, vacuum or torch brazing. In torch brazing, metals are joined by using the oxyacetylene cylinder. It thus becomes difficult to carry out brazing at the places where it is not possible to take heavy gas cylinders and brazing apparatuses. So it is tried to figure out the method to carry out brazing at places where conventional brazing...

The mechanism of lithium insertion that occurs in an iron oxyfluoride sample with a hexagonal-tungsten-bronze (HTB)-type structure was investigated by the pair distribution function. This study reveals that upon lithiation, the HTB framework collapses to yield disordered rutile and rock salt phases followed by a conversion reaction of the fluoride phase toward lithium fluoride and nanometer-siz...

Use of hydrogen in fuel cells requires catalysts that are tolerant to oxygen and are able to function in the presence of poisons such as carbon monoxide. Hydrogen-cycling catalysts are widespread in the bacterial world in the form of hydrogenases, enzymes with unusual active sites composed of iron, or nickel and iron, that are buried within the protein. We have established that the membrane-bou...