The powders of boron carbide are usually synthesized by the carbothermal reduction of boron oxide. As an alternative to high-temperature reactions, the development of the carbothermal reduction of organic precursors to produce B₄C is receiving considerable interest. The aim of this work was to compare two methods of preparing different saccharide precursors mixed with boric acid with a molar ratio of boron to carbon of 1:9 for the synthesis of B₄C. In the first method, aqueous solutions of saccharides and boric acid were dried overnight at 90 °C and pyrolyzed at 850 °C for 1 h under argon flow. In the second method, aqueous solutions of different saccharides and boric acid were freeze-dried and prepared in the same way as in the first method. Precursors from both methods were heat-treated at temperatures of 1300 to 1700 °C. The amount of boron carbide in the powders depends on the saccharides, the temperature of synthesis, and the method of precursor preparation.

A series of Mn_x(Y_0.148Zr_0.852)_1−xO_2−δ ceramics was systematically studied by means of X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) and DC magnetic susceptibility. The XAS and XES results show the changes in manganese oxidation state and a gradual evolution of the local atomic environment around Mn ions upon increasing dopant contents, which is due to structural relaxation caused by the growing amount of oxygen vacancies. Magnetic susceptibility measurements reveal that Mn₃O₄ precipitates are formed for x ≥ 0.1 and enable independent determination of the actual quantity of Mn ions dissolved in Yttria Stabilized Zirconia (YSZ) solid solution. We show that the amount of oxygen vacancies generated by manganese doping into YSZ is limited to ∼0.17 per formula unit.

The origin of nematicity and its relation to superconductivity in iron pnictide high-temperature superconductors remains unclear. One of its possible sources is the uneven occupation of Fe $d_{xz}$ and $d_{yz}$ orbitals. Here, by using x-ray linear dichroism technique, we show that such an imbalance is present in $\mathrm{Eu}{\left({\mathrm{Fe}}_{1-x}{\mathrm{Co}}_x\right)}_2{\mathrm{As}}_2$ single crystals deep in the tetragonal phase and also in the superconducting state, where we find that the $d_{xz}$ orbital has a higher occupation as indicated by an x-ray linear dichroism magnitude of 1.5%. Our result shows the importance of orbital polarization in the theoretical description of nematicity and superconductivity, particularly for determination of the superconducting gap symmetry, which is affected by orbital fluctuations.

Manganese-doped (Mn/Ti = 0.02/0.98) SrTiO₃-based materials with various Sr/Ti mole ratios (1.02, 1.00, 0.97 and 0.92) were obtained by the citrate precursor method. The materials were characterised in terms of microstructure (SEM), structure (XRD, XANES), electrical properties (DC method) and reducibility (TPR). With the introduction of 2 mol.% Mn, the cubic structure of SrTiO₃ is preserved, but significantly limits (from Sr/Ti ≥ 0.8 to Sr/Ti > 0.92) the possibilities of deviations from stoichiometry at 1200°C. The narrowing of the stability limit of the perovskite structure to Sr/Ti > 0.97 with an increase in temperature to 1400°C and segregation of Ti-Mn-enrich species are shown. The location and the oxidation states of Mn in both (Sr and Ti) sublattices depend on the assumed Sr/Ti ratio and sintering temperature. Regardless of the Sr/Ti ratio, Mn-doped SrTiO₃ exhibits very low electrical conductivity with an ionic conductivity mechanism. Graphical abstract

The series of Mnx(Y0.148Zr0.852)1-xO2-{\delta} ceramics was systematically studied by means of X-ray absorption and emission spectroscopy and DC magnetic susceptibility. XAS and XES results show changes in manganese oxidation state and a gradual evolution of the local atomic environment around Mn ions upon increasing dopants content, which is due to structural relaxation caused by growing amount of oxygen vacancies. Magnetic susceptibility measurements reveal that Mn3O4 precipitates are formed for x greater than or equal to 0.1 and enable independent determination of actual quantity of Mn ions dissolved in YSZ solid solution. We show that amount of oxygen vacancies generated by manganese doping into YSZ is limited to 0.19 per formula unit.