Three representative oxides of the La(2/3)(-)(x)()Li(3)(x)()TiO(3) system have been studied by selected area electron diffraction (SAED), high-resolution transmission microscopy (HRTEM), and powder synchrotron X-ray diffraction. HRTEM showed that materials a complex microstructure. The SAED results allowed us to propose model refine crystal structure these also accounts for their perovskite-related with diagonal unit cell ( radical 2a(p) x 2a(p)) as consequence tilting TiO(6) octahedra....

Transmission electron microscopy studies of the perovskite NaLaMgWO 6 reveal formation a complex, compositionally modulated structure. Annular dark field scanning transmission images and microscopy-electron energy-loss spectroscopy scans show that this modulation involves repeating pattern La-rich La-poor stripes, each stripe p or approximately 24 A wide (where is edge length simple cubic unit cell). High-resolution clearly show, diffraction patterns confirm, periodicity 12 along either...

The La2–xNiTiO6−δ (0 ≤ x < 0.2) series has been investigated in order to assess its possible use as a solid oxide fuel cell (SOFC) cathode material. These perovskite-like oxides exhibit monoclinic symmetry, determined by of high-resolution structural techniques (X-ray diffraction (XRD), neuron powder (NPD), selected-area electron (SAED), and transmission microscopy (TEM)). Ni Ti over the B-site and, unusually, for > 0, A-site ions are also ordered along c-axis alternate La-rich □-rich layers...

Cation ordering in the 1322 perovskite CaCu3Fe2Nb2O12 has been investigated by synchrotron X-ray diffraction structure analysis, high-resolution electron microscopy, and magnetic measurements. All of samples have full 1:3 Ca Cu cations at A-sites, but Fe Nb B sites show different degrees depending on synthesis conditions. A slow-cooled sample almost complete rock-salt-type 1:1 cation sites, a rapidly cooled no long-range B-cation arrangement. The ordered compound shows large saturated...

We have found that for the lanthanum/lithium titanates and related materials with a perovskite-related structure, ABO3, optimum lithium conductivity takes place particular concentration of A-cation vacancies (□) equal to 8%. prepared new oxide highest reported date crystalline material (σ295 K = 2.95 × 10-3 Scm-1). This is La0.56Li0.36□0.08Ti0.97Al0.03O3, x 0.03 composition in solid solution general formula La0.56Li0.33+x□0.11-xTi1-xAlxO3 (0 ≤ 0.06). A similar situation obtained system...

Electron, neutron, and synchrotron X-ray diffraction together with transmission electron microscopy studies reveal the spontaneous formation of a complex superlattice in bulk samples perovskite KLaMnWO6. The structure, which possesses P4̅2m space group symmetry = 40.0637(7) Å c 8.1306(3) Å, results from two-dimensional compositional modulation A-site cations (K+ La3+), combined pattern tilts involving corner connected octahedra. basic octahedral tilting involves out-of-phase neighboring...

Cation non-stoichiometry is now recognised to have a significant influence on the electrical-transport properties of proton-conducting oxides. The effects A-site-cation deficiency in Sr1−xCe0.9Yb0.1O3−δ perovskite system with potential use electrochemical devices are examined. Electron diffraction used verify orthorhombic structure (space group, Pnma) compositions 0 ≤ x 0.06. Combined Rietveld refinements high-resolution neutron and X-ray data confirm previously reported anomalous evolution...

Charge ordering and oxygen vacancy are revealed in REBaMn 2 O 6‐ δ (RE = Gd, Tb) oxides with perovskite‐related structures. Electron diffraction transmission electron microscopy results indicate a modulation of the crystal structure. The average oxidation state Mn stoichiometry determined by means energy‐loss spectroscopy, giving 5.75 general formula. A 1:3 4+ :Mn 3+ charge model is confirmed neutron powder diffraction, vacancies‐Mn association suggested pair distribution function analysis....

The stoichiometry range, crystal chemistry, ionic conductivity, and electrochemical window of the La2/3LixTi1-xAlxO3 system with perovskite-related structure have been studied. range existence solid solution is (0.06 = x 0.3). Powder X-ray diffraction transmission electron microscopy results show that these oxides a unit cell multiple perovskite dimensions ≈ √2ap, b c 2ap. conductivity materials its dependence on composition temperature examined by complex impedance spectroscopy. Lithium ion...

Dense Ce0.8Pr0.2O2−δ ceramic membranes with submicron grain size can be formed at 1000 °C by minor additions of cobalt oxide. X-ray energy-dispersive spectroscopy shows the additive to located in boundary. Although a very fine interface is obtained for composition containing 2 mol % oxide, pronounced boundary layers and Co-rich fringes are noted 5 %. The oxide enhance electronic conductivity around 2−3 times. For additions, no change level or nature ionic observed, whereas %, depleted lower...

A combination of selected-area electron diffraction (SAED), neutron powder (NPD) and high-resolution transmission microscopy (HRTEM) reveals a complex superstructure in the ordered perovskite NaLaMgWO 6 . Through indexing SAED patterns unit-cell dimensions are found to be 46.8 × 7.8 7.9 Å, which corresponds 12 p 2 simple Pm\overline 3 m unit cell. HRTEM images reveal formation an unmistakable stripe contrast that repeats with same periodicity. Doubling b c axes is brought about by layered...

The microstructures of different high-temperature prepared oxides the (1−x)Y0.5Zr0.5O1.75−xY0.75Nb0.25O1.75 (0 ≤ x 1) system have been studied by selected-area electron diffraction and high-resolution transmission microscopy. materials show a modulated fluorite-type structure mainly due to partial or short-range ordering oxygen vacancies. modulation is related pyrochlore-type in Y0.75Nb0.25O1.75. A vacancies C-type observed Y0.5Zr0.5O1.75. Gradual transition from pyrochlore structures...

Progress in the design of functional perovskite oxides relies on advances density theory (DFT) methods to efficiently and effectively model complex systems composed several transition-metal ions. This work reports application DFT investigate electronic structure YSr2Cu2FeO8−δ (0 < δ 1) family which insulating, metal, or superconducting behaviors even anion conductivity can be tuned by modifying oxygen content. In particular, we assess performance generalized gradient approximation (GGA), its...

We demonstrate that temporal characterization of ultrabroadband laser pulses (∼ 7 fs) through the d-scan technique can be implemented using ensembles SHG micro and/or nanocrystals independently their crystal size composition. The experimental results have been supported by numerical simulations based on Finite-Difference-Time-Domain (FDTD) algorithm. Both, experiment and show that, in spite low optical quality samples unavoidable appearance incoherent light, is robust allows to measure...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Susana García-Martín, Ainhoa Morata-Orrantia, Myriam H. Aguirre, Miguel Á. Alario-Franco; Giant barrier layer capacitance effects in the lithium ion conducting material La0.67Li0.25Ti0.75Al0.25O3. Appl. Phys. Lett. 24 January 2005; 86 (4): 043110. https://doi.org/10.1063/1.1852717 Download citation file: Ris...

The structures of the doubly ordered perovskites NaCeMnWO6 and NaPrMnWO6, with rock salt ordering Mn2+ W6+B-site cations layered Na+ (Ce3+/Pr3+) A-site cations, have been studied by transmission electron microscopy, diffraction, neutron synchrotron X-ray powder diffraction. Both compounds possess incommensurately modulated crystal structures. In modulation vector (with reference to ideal ABX3 perovskite subcell) is q ≈ 0.067a* (∼58.7 Å) in NaPrMnWO6q 0.046a* (∼85.3 Å). both superstructures...

GdBaCo_2−xFe_xO_5+δ oxides show crystal structures and ASR values dependent on the composition synthesis atmosphere. A new modulation of structure is found for material with <italic>x</italic> = 0.6.

GdBaCo_2−xMn_xO_5+δ is a new system of layered perovskites displaying better electrochemical properties when layered-type ordering Gd and Ba cations adopted.

Strontium cerate (SrCeO(3)) is the parent phase of a family prototype proton-conducting perovskites with important potential applications as electrolytes in protonic ceramic fuel cells, hydrogen-separation membranes, and sensors for hydrogen humidity. Apparent nonstoichiometric behavior microstructure SrCeO(3) have been investigated. Phase analysis by X-ray diffraction indicates that single-phase material system Sr(1+x)CeO(3+)delta obtained compositions x = 0.02-0.03 nominally stoichiometric...

Abstract The very high value of ionic conductivity at room temperature reported for La 0.51 Li 0.34 TiO 2.94 some years ago did originate a great deal interest in the study materials general formula 2/3– x 3 (LaLiTiO) and related systems. These oxides have shown to be potential solid electrolytes lithium secondary batteries, but other aspects, apart from conducting properties, such as their dielectric behaviour crystal structure, been main focus important studies area inorganic solid‐state...