227 research outputs found

    Electronic structure of CePtIn and LaPtIn compounds

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    The electronic structure of the ternary RPtIn (R = La, Ce) compounds, which crystallize in the hexagonal ZrNiAl-type structure, was studied by X-ray photoelectron spectroscopy measurements and calculation using the ab initio methods (linear mu n-tin orbital in the atomic sphere approximation, full potential linear mu n-tin orbital, full potential linear orbital). The results showed that the valence band in these compounds is formed by the Pt 5d and In 5s and 5p states. The band calculations with spin orbit coupling have shown that the Ce 4f peaks consist of two peaks above the Fermi level that correspond to the Ce 4f7=2 and 4f5=2 doublet and wide peaks corresponding to the La 4f states. The analysis of Ce 3d spectra on the basis of the Gunnarsson Schönhammer model gives hybridization of 4f orbitals with the conduction electron band equal to 170 meV

    Electronic structure of CePtIn and LaPtIn compounds

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    The electronic structure of the ternary RPtIn (R = La, Ce) compounds, which crystallize in the hexagonal ZrNiAl-type structure, was studied by X-ray photoelectron spectroscopy measurements and calculation using the ab initio methods (linear mu n-tin orbital in the atomic sphere approximation, full potential linear mu n-tin orbital, full potential linear orbital). The results showed that the valence band in these compounds is formed by the Pt 5d and In 5s and 5p states. The band calculations with spin orbit coupling have shown that the Ce 4f peaks consist of two peaks above the Fermi level that correspond to the Ce 4f7=2 and 4f5=2 doublet and wide peaks corresponding to the La 4f states. The analysis of Ce 3d spectra on the basis of the Gunnarsson Schönhammer model gives hybridization of 4f orbitals with the conduction electron band equal to 170 meV

    XPS Study of Superconducting LiTi2O4 and LiTi2-xCuxO4 Sol-Gel Derived Powders and Thin Films

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    In this work X-ray photoelectron studies of lithium titanate and copper doped lithium titanate are presented. Both, powder and thin lms samples were prepared by sol gel method. After preparation, the samples were heated in argon atmosphere at various temperatures in a range from 500 ◦C to 600 ◦C for 20 h. The crystalline structure of the samples was investigated by X-ray di raction, while the oxidation states of the elements were examined by X-ray photoelectron spectroscopy method. X-ray di raction measurements con rmed spinel phase of all manufactured samples. However it is well known that electrical and superconducting properties of lithium titanate are strongly correlated not only with structure, but also with oxidation state of Ti ions. X-ray photoelectron spectroscopy investigations revealed mixture of Ti3+ and Ti4+ ions, although the Ti3+/Ti4+ ratio is much smaller than 1 2 needed for superconductivity. In this work dependence between calcination temperature as well as amount of Cu dopant and Ti3+/Ti4+ proportion are reported

    Mixed-valence state in Yb2CuGe6

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    We present here temperature dependent X-ray photoemission measurements on polycrystalline Yb2CuGe6. The analysis of these data shows the change in the effective valence, determined directly from the 4f intensity ratio, as a function of temperature

    Fatigue properties of Ti6Al4V cellular specimens fabricated via SLM: CAD vs real geometry

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    Abstract Fully dense titanium alloy implants have long been used for the replacement and stabilization of damaged bone tissue. Nevertheless, they can cause stress shielding which brings to a loss of bone mass. Additive manufacturing (AM) allows obtaining highly porous cellular structures with a wide range of cell morphologies to tune the mechanical properties to match that of the patient's bone. In this work, the fully reversed fatigue strength of cellular specimens produced by Selective Laser Melting (SLM) of Ti-6Al-4V alloy was measured. Their structures are determined by cubic cells packed in six different ways and their elastic modulus is roughly 3GPa to match that of trabecular bone. Part of the specimens was left as sintered and part treated by Hot Isostatic Pressing (HIP). The fatigue resistance of such AM parts can be affected by surface morphology, geometrical accuracy as well as internal defects. Micro X-ray computed tomography (CT) was used in this work to compare the geometry of the produced specimens with the CAD model and to carry out residual stress measurements using the Plasma FIB-SEM-DIC micro-hole drilling method

    Superconducting properties of VN-SiO 2 sol-gel derived thin films

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    In this work studies of structure and superconducting properties of VN SiO2 lms are reported. The lms were obtained through thermal nitridation (ammonolysis) of sol gel derived V2O3 SiO2 coatings (in a proper V2O3/SiO2 ratio) at 1200 ◦ C. This process leads to the formation of disordered structure with VN metallic grains dispersed in the insulating SiO2 matrix. The structural transformations occurring in the lms as a result of ammonolysis were studied using X-ray photoelectron spectroscopy (XPS). The critical superconducting parameters are obtained. The magnetoresistance at high magnetic elds has been investigated

    Allogeneic hematopoietic stem cell transplantation for inherited disorders: Experience in a single-center

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