We report the first successful preparation of thin films Y-Ba-Cu-O superconductors using pulsed excimer laser evaporation a single bulk material target in vacuum. Rutherford backscattering spectrometry showed composition these to be close that material. Growth rates were typically 0.1 nm per shot. After an annealing treatment oxygen exhibited superconductivity with onset at 95 K and zero resistance 85 75 on SrTiO3 Al2O3 substrates, respectively. This new deposition method is relatively...

Perovskites (ABO3) with transition metals in active B sites are considered alternative catalysts for the water oxidation to oxygen through evolution reaction (OER) and reduction (ORR) back water. We have synthesized a double perovskite (A2BB'O6) different cations A, B, B' sites, namely, (La1.5Sr0.5)A(Ni0.5Mn0.5)B(Ni0.5Ru0.5)B'O6 (LSNMR), which displays an outstanding OER/ORR bifunctional performance. The composition structure of oxide has been determined by powder X-ray diffraction, neutron...

We report the observation of large low-field magnetoresistance (MR) behavior in ${\mathrm{CaCu}}_{3}{\mathrm{Mn}}_{4}{\mathrm{O}}_{12}$ with a perovskite-related $({\mathrm{AA}}^{\ensuremath{'}}_{3}B_{4}{\mathrm{O}}_{12})$ structure. ${\mathrm{Ca}}^{2+}{\mathrm{Cu}}_{3}^{2+}{\mathrm{Mn}}_{4}^{4+}{\mathrm{O}}_{12}$ is semiconducting and orders ferromagnetically at 355 K. However, it has neither mixed valency Mn for double-exchange magnetic interactions, nor Jahn-Teller ${\mathrm{Mn}}^{3+}$...

Double-perovskites Sr2MMoO6 (M = Co, Ni) have been investigated as anode materials for a solid oxide fuel cell. At room temperature, both Sr2CoMoO6 and Sr2NiMoO6 are tetragonal (I4/m). X-ray absorption spectroscopy confirmed the presence of Co2+/Mo6+ Ni2+/Mo6+ pairs in oxygen-stoichiometric compounds. The samples contain limited concentration oxygen vacancies reducing atmospheres at an anode. Reoxidation is facile below 600 °C; they become antiferromagnetic low temperatures TN 37 80 K M Co...

Systematic Mn K-edge x-ray-absorption spectroscopy (XAS) measurements on samples of ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Ca}}_{\mathrm{x}}$${\mathrm{MnO}}_{3}$ are reported. Detailed results the chemical shift and pre-edge feature spectral strength (both indicators d-hole count) discussed. The overall across series is compared to standard materials consistent with identification endpoint perovskites ${\mathrm{Mn}}^{3+}$ ${\mathrm{Mn}}^{4+}$ states. detailed...

A Bi2O3 in β-MnO2 composite cathode material has been synthesized using a simple hydrothermal method and cycled mixed KOH–LiOH electrolyte with range of concentrations. We show that, at KOH:LiOH molar ratio 1:3, both proton insertion lithium occur, allowing access to higher fraction the theoretical capacity MnO2 while preventing formation ZnMn2O4. This enables 360 mAh/g for over 60 cycles, cycling limited more by anode properties than traditional cathodic failure mechanisms. The structural...

Li3V2(PO4)3/C (LVP/C) coated with various amounts of SiO2 has been synthesized, and the effect surface modification by on performance LVP systematically investigated X-ray diffraction (XRD), photoelectron spectroscopy (XPS), absorption (XAS), scanning electron microscopy (SEM), transmission (TEM), magnetic susceptibility, Raman spectroscopy, electrochemical measurements. Based analysis XRD, XPS, TEM, it is confirmed that coating particles does not change monoclinic structure LVP. The XAS,...

The first transition-metal-only double perovskite compound, Mn(2+) 2 Fe(3+) Re(5+) O6 , with 17 unpaired d electrons displays ferrimagnetic ordering up to 520 K and a giant positive magnetoresistance of 220 % at 5 8 T. These properties result from the ferrimagnetically coupled Fe Re sublattice are affected by two-to-one magnetic-structure transition Mn when magnetic field is applied. Theoretical calculations indicate that half-metallic state can be mainly attributed spin polarization sites.

A series of LiFe1–xVxPO4/C samples have been successfully prepared using a two-step solid-state reaction route. The effect vanadium incorporation on the performance LiFePO4 has systematically investigated with X-ray diffraction, Raman spectroscopy, charge/discharge measurements, and cyclic voltammetry tests. It is found that V significantly enhances electrochemical LiFePO4. Particularly, LiFePO4/C sample 5 at. % doping exhibits best specific discharge capacity 129 mAh g–1 at 5.0 C after 50...

We demonstrate a facile ligand-assisted synthetic method, promoting the transformation of 2D layered double hydroxides (LDHs) into metal–organic frameworks (MOFs) with superior water oxidation reaction performance and durable stability.

Nanosized, carbon-coated LiFePO4 (LFP) is a promising cathode for Li-ion batteries. However, nano-particles are problematic electrode design, optimized electrodes requiring high tap densities, good electronic wiring, and low tortuosity efficient Li diffusion in the electrolyte between solid particles, conditions that difficult to achieve simultaneously. Using situ energy-dispersive X-ray diffraction, we map evolution of inhomogeneous electrochemical reaction LFP-electrodes. On first cycle,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrigin of Polychromism Cis Square-Planar Platinum(II) Complexes: Comparison Two Forms [Pt(2,2'-bpy)(Cl2]R. H. Herber, M. Croft, J. Coyer, B. Bilash, and A. SahinerCite this: Inorg. Chem. 1994, 33, 11, 2422–2426Publication Date (Print):May 1, 1994Publication History Published online1 May 2002Published inissue 1 1994https://pubs.acs.org/doi/10.1021/ic00089a018https://doi.org/10.1021/ic00089a018research-articleACS PublicationsRequest reuse...

${\mathrm{CaMnO}}_{3\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ with $\ensuremath{\delta}=0,$ 0.06, and 0.11 was prepared by the Pechini citrate gel process at 1100 \ifmmode^\circ\else\textdegree\fi{}C. Oxygen defects were created quenching sample from high temperature. Chemical analysis x-ray absorption show that formal valence of Mn in ${\mathrm{CaMnO}}_{3}$ is close to 4+, Mn(III) quenched samples. Moreover near-edge spectra results support creation two five coordinate sites for...

The pulsed laser thin-film deposition process can enable preparation of thin films complex composition with good control over the film stoichiometry. compositions are similar to that target pellet and as a consequence this technique appears be an ideal method for preparing high Tc on variety substrates.The factors which contribute beneficial phenomenon have been explored by ionization mass spectrometry (LIMS) post ablation (PAI) neutral velocity analysis in order determine velocities ejected...

New mixed-valent, Ni1+/Ni2+, metastable nickelate, La3Ni2O6, was synthesized by low-temperature reduction of La3Ni2O7 with CaH2. The crystal structure La3Ni2O6 (space group: I4/mmm, a = 3.9686(1) A and c 19.3154(6) A) determined from powder neutron diffraction data Rietveld analysis. can be described as an intergrowth LaO2 fluorite double infinite layer (LaNiO2)2 blocks represents the n 2 homologue T'-type series Lan+1NinO2n+2. Such structural arrangement has never been observed before....

We report core-level spectroscopic measurements of several cuprate perovskites comparing those which exhibit superconductivity above 90 K to others do not. Both x-ray photoemission and absorption results show that in the former Cu is more oxidized, as CuO (nominally ${\mathrm{Cu}}^{2+}$), than latter. Trivalent clearly excluded. The O $1s$ core level at higher binding energy superconductors, implying presence $2p$ holes. rare-earth valence Ce- Pr-based 3+, apparently related their failure...

Experiments on CeP, CeAs, and CeBi have revealed two $4f$-derived photoemission features at binding energies of 0.6 eV [FWHM (full width half maximum)\ensuremath{\sim}0.7 eV] 3.0-3.1 (FWHM \ensuremath{\sim} 1.0 eV) due to competing Ce $4f$ photoionization channels. The relative intensity the spectral changes by 10 from CeP CeBi. These findings indicate strong $f\ensuremath{-}p$ hybridization force a reevaluation previous in compounds.

Photoelectron-spectroscopy studies of Ce${\mathrm{Al}}_{2}$, La${\mathrm{Al}}_{2}$, and the "chemically compressed" alloys ${\mathrm{Ce}}_{0.6}$${\mathrm{Y}}_{0.4}$${\mathrm{Al}}_{2}$ ${\mathrm{Ce}}_{0.6}$${\mathrm{Sc}}_{0.4}$${\mathrm{Al}}_{2}$ were performed with use synchrotron radiation. For all compounds $4f$ binding energy is 2.55 \ifmmode\pm\else\textpm\fi{} 0.1 eV. These results, combined previous bulk-property motivate a reevaluation Anderson-model parameters mechanisms as applied...

Polar LiNbO3-type magnetic oxides have been extended, for the first time, to A2BB′O6 family. Mn2+2Fe3+M5+O6 (M=Nb, Ta), synthesized at high pressure, adopt a polar structure, as demonstrated by electron diffraction and second harmonic generation effect, they interesting properties. As service our authors readers, this journal provides supporting information supplied authors. Such materials are peer reviewed may be re-organized online delivery, but not copy-edited or typeset. Technical...

Polar oxides are technically of great interest but difficult to prepare. Our recent discoveries predicted that polar can be synthesized in the corundum-derivative A2BB'O6 family with unusually small cations at A-site and a d(0) electron configuration ion B'-site. When magnetic transition-metal ions incorporated more interesting form. In this work we experimentally verified prediction prepared LiNbO3 (LN)-type Zn2FeTaO6 via high pressure temperature synthesis. The crystal structure analysis...

Energy dispersive X-ray diffraction (EDXRD) with photons of high energy and flux is used to map crystalline discharge products within alkaline AA cells following at various rates: C/160, C/80, C/40, C/20, C/10, C/5. During the study, sealed are never opened thus exposed air. The technique's resolution allows manganese oxide be distinguished, which has previously proven difficult. In particular, colocalized Mn3O4 (hausmannite) ZnMn2O4 (hetaerolite) phases resolved C/40 rates. Following more...

Recently CsTlCl3 and CsTlF3 perovskites were theoretically predicted to be potential superconductors if they are optimally doped. The synthesis of these two compounds, together with a complete characterization the samples reported. is obtained as orange crystals in different polymorphs: tetragonal (I4/m) cubic (Fm-3m) phase. formed light brown powder, also double perovskite (Fm-3m). In all three CsTlX3 phases Tl1+ Tl3+ located crystallographic positions that accommodate their bond lengths....