Thermodynamic stability of non-stoichiometric SrFeO: a hybrid DFT study.

SrFeO3-δ is a mixed ionic-electronic conductor with a complex magnetic structure that reveals a colossal magnetoresistance effect. This material and its solid solutions are attractive for various spintronic, catalytic and electrochemical applications, including cathodes for solid oxide fuel cells and permeation membranes. Its properties strongly depend on oxygen non-stoichiometry.

Thermodynamic stability of stoichiometric LaFeO and BiFeO: a hybrid DFT study.

BiFeO perovskite attracts great attention due to its multiferroic properties and potential use as a parent material for BiSrFeO and BiSrFeCoO solid solutions in intermediate temperature cathodes of oxide fuel cells. Another iron-based LaFeO perovskite is the end member for well-known solid solutions (LaSrFeCoO) used for oxide fuel cells and other electrochemical devices. In this study an ab initio hybrid functional approach was used for the study of the thermodynamic stability of both LaFeO and BiFeO with respect to decompositions to binary oxides and to elements, as a function of temperature and oxygen pressure.

Density functional calculations of extended, periodic systems using Coulomb corrected molecular fractionation with conjugated caps method (CC-MFCC).

A fragmentation scheme based upon the molecular fractionation with conjugated caps (MFCC) method and derived previously [J. Chem. Phys.

The first-principles treatment of the electron-correlation and spin-orbital effects in uranium mononitride nuclear fuels.

The DFT+U calculations were employed in a detailed study of the strong electron correlation effects in a promising nuclear fuel-uranium mononitride (UN). A simple method for solving the multiple minima problem in DFT+U simulations and insure obtaining the correct ground state is suggested and applied. The crucial role of spin-orbit interactions in reproduction of the U atom total magnetic moment is demonstrated.

Fast oxygen exchange kinetics of pore-free Bi(1-x)Sr(x)FeO(3-δ) thin films.

The oxygen incorporation/extraction kinetics of the potential solid oxide fuel cell (SOFC) cathode material Bi(1-x)Sr(x)FeO(3-δ) with x = 0.5 and 0.8 was studied by electrochemical impedance spectroscopy on geometrically well-defined pore-free thin film electrodes.

Density functional theory calculations on magnetic properties of actinide compounds.

We have performed a detailed analysis of the magnetic (collinear and non-collinear) order and the atomic and electron structures of UO(2), PuO(2) and UN on the basis of density functional theory with the Hubbard electron correlation correction (DFT + U). We have shown that the 3-k magnetic structure of UO(2) is the lowest in energy for the Hubbard parameter value of U = 4.6 eV (and J = 0.

Ab initio DFT+U study of He atom incorporation into UO(2) crystals.

We present and discuss results of the density functional theory (DFT) for perfect UO(2) crystals with He atoms in octahedral interstitial positions therein. We have calculated basic bulk crystal properties and He incorporation energies into the low temperature anti-ferromagnetic UO(2) phase using several exchange-correlation functionals within the spin-polarized local density (LDA) and generalized gradient (GGA) approximations. In all DFT calculations we included the on-site correlation corrections using the Hubbard model (DFT+U approach).

Adsorption of atomic and molecular oxygen on the LaMnO3(001) surface: ab initio supercell calculations and thermodynamics.

We present and discuss the results of ab initio DFT plane-wave supercell calculations of the atomic and molecular oxygen adsorption and diffusion on the LaMnO(3) (001) surface which serves as a model material for a cathode of solid oxide fuel cells. The dissociative adsorption of O(2) molecules from the gas phase is energetically favorable on surface Mn ions even on a defect-free surface. The surface migration energy for adsorbed O ions is found to be quite high, 2.