Related papers: Stoichiometric oxygen content in NaxCoO2
We present a detailed room temperature x-ray powder diffraction study on La2-xSrxNiO4+d with 0<=x<=0.12 and 0<=d<=0.13. For x=0.02, 0.04 and 0.06 the oxygen content phase diagrams of the Sr doped samples show a similar sequence of pure…
We report a complete analysis of the formal oxidation state of Co in NaxCoO2, in the interval 0.31<x<0.67. Iodometric titration and thermoelectric power confirm that a direct relationship between the Na content and the amount of Co 3 +…
Thin films of Co-TiO2 are deposited on silicon and quartz substrates using Pulse Laser Deposition (PLD) process at various oxygen partial pressures ranging from 6.6 x 10-3 Pascals (Pa) to 53 Pa. Crystal structure, transport and magnetic…
The structural, dielectric and ferroelectric properties of lead-free (Na0.5-xKxBi0.5-xLax)TiO3 powders synthesized by sol-gel self-combustion method were investigated. Rietveld refinement of Synchrotron x-ray diffraction data confirms pure…
We present lattice-gas modeling of the steady-state behavior in CO oxidation on the facets of nanoscale metal clusters, with coupling via inter-facet CO diffusion. The model incorporates the key aspects of reaction process, such as rapid CO…
We investigated the crystal structure, magnetic behavior, and optical properties of the layered honeycomb compound Na2Cu2TeO6. X-ray and neutron diffraction confirmed a monoclinic structure, with Cu ions arranged in dimerized chains.…
We use ab initio simulations to study the static and dynamic properties of a sodium borosilicate liquid with composition 3Na_2O-B_2O_3-6SiO_2, i.e. a system that is the basis of many glass-forming materials. In particular we focus on the…
The ordering of Na ions in Na$_x$CoO$_2$ is investigated systematically by combining detailed density functional theory (DFT) studies with model calculations. Various ground state ordering patterns are identified, and they are in excellent…
We performed neutron powder diffraction measurements on the as-sintered (AS) and oxygen-reduced (OR) La$_{1.8}$Eu$_{0.2}$CuO$_{4+\alpha-\delta}$ (LECO). The structural parameters for oxygens in AS and OR samples refined by the Rietveld…
Isolated oxygen impurities and fully oxidized structures of four stable two-dimensional (2D) SiS structures are investigated by {\em ab initio} density functional calculations. Binding energies of oxygen impurities for all the four 2D SiS…
Results of X-ray diffraction experiments on solid oxygen at low temperature and at pressures up to 10 GPa are presented.A careful sample preparation and annealing around 240 K allowed to obtain very good diffraction patterns in the…
Sodium-ion batteries (SIBs) have received significant attention as promising alternative for energy storage applications owing to the large availability and low cost of sodium. In this paper we study the electrochemical behavior of…
We systematically study Raman spectroscopy of cleaved Na$_x$CoO$_2$ single crystals with 0.37 $\leq$ x $\leq$ 0.80. The Raman shift of A$_{1g}$ mode is found to be linearly dependent on Na content, while the Raman shift of E$_{1g}$ mode has…
Using density-functional theory (DFT) we calculate the Gibbs free energy to determine the lowest-energy structure of a RuO_2(110) surface in thermodynamic equilibrium with an oxygen-rich environment. The traditionally assumed stoichiometric…
Neutron and x-ray powder diffraction have been used to investigate the crystal structures of a sample of the newly-discovered superconducting sodium cobaltate deuterate compound with composition Na0.31(3)CoO2o1.25(2)D2O and its anhydrous…
Oxygen vacancies in nickelates are known to introduce a variety of emergent phenomena and are considered to significantly affect conductivity. Few studies have examined real-space evidence for oxygen vacancies on the surface, particularly…
We report that Na2IrO3, which has a layered honeycomb iridium oxide sublattice interleaved by Na planes, decomposes in laboratory air while maintaining the same basic crystal structure. The decomposition reaction was monitored by…
We present a detailed atomistic picture of the oxidation mechanism of Co nanoparticles and its impact on magnetism by experimentally following the evolution of the structure, chemical composition, and magnetism of individual, gas-phase…
The local structure and oxidation state of the cobalt impurity in SrTiO$_3$ is studied by X-ray absorption fine structure (XAFS) spectroscopy. The synthesis conditions, under which cobalt predominantly (up to 76%) substitutes the atoms at…
We present the results of large scale computer simulations in which we investigate the static and dynamic properties of sodium disilicate and sodium trisilicate melts. We study in detail the static properties of these systems, namely the…