Jiri Hejtmanek

Single-phase region of the 2212-BiSrCaCuO superconductor

Abstract The phase relationships and solid-solution region of the Bi 2 Sr 2 CaCu 2 O 8+δ (2212) superconductor were investigated at 850°C under air atmosphere in a cross-section of the system BiSrCaCu(O) defined by the formula Bi 2+ y Sr 3− y − x Ca x Cu 2 O 8+δ . The system was studied by means of XRD and EMA and an approximate position of the 2212 single-phase region is delimited by the values of y =0.1 and 0.8≤ x ≤1.3. The single-phase region determined may be divided into two subregions, Sr-rich in the range 0.8≤ x ≤1.0 and Ca-rich in the range 1.1≤ x ≤1.3, these differing in the number and character of intergrowths. The highest superconducting transition temperature ( T c ) was found for x =0.8.

Synthesis of HgBa2CuO4+δ by sol–gel method under controlled oxygen pressure; electron and thermal transport properties

Abstract Samples of mercury superconductor HgBa2CuO4+δ were prepared employing highly homogeneous and reactive precursor Ba2CuO3+x obtained by the sol–gel method. Mixture of Mn3O4/Mn2O3 was used to adjust p(O2) during the synthesis. This approach allows to achieve the appropriate p(O2) at the reaction temperature 720°C and multizone furnace is not required. The enhancement of the thermal conductivity below Tc, measured for the first time in Hg-type superconductor, indicates unusually strong phonon–electron coupling. The enhancement is accompanied by a sharp resistivity and thermopower decrease.

Metal-insulator transition and the Pr3+/Pr4+ valence shift in (Pr1-yYy)0.7Ca0.3CoO3

The magnetic, electric and thermal properties of the (

X-ray Characterization, Electronic Band Structure, and Thermoelectric Properties of the Cluster Compound Ag2Tl2Mo9Se11

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Modeling of the thermopower of electron-doped manganites

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Improvement of the magnetic shielding and trapping properties of BiPbSrCaCuO superconducting tubes by the use of multiple thermomechanical processing

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Superconductivity and electric transport of Bi2+xSr2−yCuO6+δ single crystals

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Properties of superconducting Bi-2223 tubular current leads

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Optimization of the Bi(Pb)-2223 bulk technology

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Thermoelectric Properties of In x Co 4-y Ni y Sb 12 Skutterudite Compounds

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