Doping dependent phase fractions in hydrothermally synthesized Mn doped CuFeO2

Using a simple hydrothermal method, CuFe1−xMnxO2 delafossite materials are produced and investigated by means of X-ray diffraction, ultraviolet-visible reflectance measurements, and electron microscopy. Up to nominally x = 0.3, the synthesis yields delafossite material, which generally consists of both the 2H and R3 phase without any impurities. Lattice parameters and the indirect optical band gap of delafossite close to about 1.3 eV decrease upon increasing Mn content, which confirms the successful doping with Mn up to an actual Mn content of x = 0.05. The 2H phase fraction shows a pronounced and peaked dependence on Mn content with a maximum 2H mass fraction of about 27% at nominally x = 0.01, whereas the hexagonal particle morphology and the platelet size of about 500 nm as measured by both scanning and transmission electron microscopy are independent from the latter

The Li stance on precipitation in Al–Li-based alloys: an investigation by X-ray Raman spectroscopy

Decomposition and precipitation processes in a binary Al–Li alloy and a technical Al–Li–Cu–Mg alloy were investigated using differential scanning calorimetry and X-ray Raman spectroscopy (XRS). The formation of ’ and T1 precipitates in the Al–Li and the T8 heat-treated Al–Li–Cu–Mg alloy, respectively, was confirmed using DSC. The XRS measurements complemented by simulated spectra allowed for probing specifically Li and its environment within the Al matrix. Based on linear combination fits of the XRS spectra, the relative contributions of ′ and T1 precipitates were quantified. These results are in agreement with estimates of the relative amount of Li taking part in the precipitation process. Difficulties and limitations of the application of XRS to Al alloy systems are also discussed

Quadrupole splitting and isomer shifts in Te oxides investigated using nuclear forward scattering

Nuclear forward scattering by 125Te is a viable alternative to conventional 125Te Mössbauer spectroscopy avoiding all source related issues. Using reference compounds with known hyperfine parameters and Te oxides exhibiting stereochemically active lone pairs, we show that nuclear forward scattering by 125Te can be reliably used to extract quadrupole splitting energy and relative isomer shift. The rough correlation between Te-Ocoordination and quadrupole splitting energy as put forward by Takeda and Greenwood (J. Chem. Soc. Dalton, 2207, 1975), is corroborated by the presented results