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Core-level spectroscopic studies suggest that cuprates nominally supposed to contain Cu3+ ions are likely to have the excess positive charge on oxygen instead, giving rise to O– type species (oxygen holes).

We present results of an electron paramagnetic resonance (EPR) study of Nd1−x Sr x MnO3 with x=0.5 across the paramagnetic to ferromagnetic, insulator to metal transition at 260K (T c) and the antiferromagnetic, charge ordering transition (T N=T co) at 150K. The results are compared with those on Nd0.45Sr0.55MnO3 which undergoes a transition to a homogeneous A-type antiferromagnetic phase at T N=230K and on La0.77Ca0.23MnO3 which undergoes a transition to coexisting ferromagnetic metallic and ferromagnetic insulating phases. For x=0.5, the EPR signals below T c consist of two Lorentzian components attributable to the coexistence of two phases. From the analysis of the temperature dependence of the resonant fields and intensities, we conclude that in the mixed phase ferromagnetic and A-type antiferromagnetic (AFM) phases coexist. The x=0.55 compound shows a single Lorentzian throughout the temperature range. The signal persists for a few degrees below T N. The behaviour of the A-type AFM phase is contrasted with that of the two ferromagnetic phases present in La0.77Ca0.23MnO3. The comparison of behaviour of A-type AFM signal observed in both Nd0.5Sr0.5MnO3 and Nd0.45Sr0.55MnO3 with the two FM phases of La0.77Ca0.23MnO3, vis-à-vis the shift of resonances with respect to the paramagnetic phases and the behaviour of EPR intensity as a function of temperature conclusively prove that the Nd0.5Sr0.5MnO3 undergoes phase separation into A-type AFM and FM phases.

We report our high-pressure Raman studies on single-wall carbon nanotube bundles carried out up to 25.9 GPa. The intensity of the radial modes decreases more drastically as compared to that of the tangential modes. The former could be followed up in pressure runs to 3 GPa. The most intriguing observation is the anomalous pressure behaviour of the 1594 cm−1 tangential mode between 10 and 16 GPa. This feature, as well as the pressure dependence of intensity, peak position and linewidth, are reversible on decompression. The anomalous pressure dependence is argued to be associated with faceting of the tubes in the bundle, showing their remarkable resilience.

There has been emerging interest in exploring single‐sheet 2D layered structures other than graphene to explore potentially interesting properties and phenomena. The preparation, isolation and rapid unambiguous characterization of large size ultrathin layers of MoS 2 , GaS, and GaSe deposited onto SiO 2 /Si substrates is reported. Optical color contrast is identified using reflection optical microscopy for layers with various thicknesses. The optical contrast of these thin layers is correlated with atomic force microscopy (AFM) and Raman spectroscopy to determine the exact thickness and to calculate number of the atomic layers present in the thin flakes and sheets. Collectively, optical microscopy, AFM, and Raman spectroscopy combined with Raman imaging data are analyzed to determine the thickness (and thus, the number of unit layers) of the MoS 2 , GaS, and GaSe ultrathin flakes in a fast, non‐destructive, and unambiguous manner. These findings may enable experimental access to and unambiguous determination of layered chalcogenides for scientific exploration and potential technological applications.

No abstract is provided for this article.

No abstract is provided for this article.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray spectroscopic study of chromium, nickel, and molybdenum compoundsA. Manthiram, P. R. Sarode, W. H. Madhusudan, J. Gopalakrishnan, and C. N. R. RaoCite this: J. Phys. Chem. 1980, 84, 17, 2200–2203Publication Date (Print):August 1, 1980Publication History Published online1 May 2002Published inissue 1 August 1980https://pubs.acs.org/doi/10.1021/j100454a018https://doi.org/10.1021/j100454a018research-articleACS PublicationsRequest reuse permissionsArticle Views223Altmetric-Citations30LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Nanocomposites formed by carboxyl-functionalized MoS2 nanotubes with poly(diallyldimethylammonium chloride) (PDDA, described as P)-modified single-walled carbon nanotubes (SWCNT) and borocarbonitride nanotubes (BCNNT) have been prepared by a solution-phase flocculation of 1D nanotubes. The nanocomposites show higher photocatalytic and electrocatalytic HER activities compare to the individual constituents, where the H2 yield improves with the MoS2 nanotube proportion. The maximum H2 evolution rate achieved is 7475 μmol g–1 h–1 in the nanocomposite of MoS2–P.SWCNT with a MoS2–P.SWCNT proportion of 3:1, whereas the corresponding physical mixture exhibits only 3112 μmol g–1 h–1. The MoS2–P.SWCNT (3:1) nanocomposite also shows superior electrocatalytic H2 evolution with an onset potential of 80 mV (vs RHE). The MoS2–P.BCNNT composite exhibits a somewhat lower H2 evolution rate. Electrostatic stacking of 1D MoS2 nanotubes with SWCNT/BCNNT appears to be a valuable strategy for HER and related catalytic reactions.

Ferromagnetic resonance spectra of La1−xCaxMnO3 powders (0.1 ≤ x ≤ 0.9) have been investigated over a range of temperatures. The spectra could be fitted to a sum of two Lorentzlans for all the compositions. The intense line with a nearly constant g shows a linear decrease in linewidth with increase in temperature, while the weaker line with a variable g shows a maximum in linewidth in the TC region. The latter is also associated with a geff which depends on the composition.