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1

Influence of conditions of synthesis on superconductivity in Nd2-xCexCuO4-y

Plebańczyk M., Klimczuk T., Gortenmulder T., Fiertek P., Sadowski W.

Materials Science Poland

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2006

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Vol. 24, No. 4

991--1002

EN

Samples of Nd1.85Ce0.15CuO4 were prepared using two different methods of synthesis (series A and B). The superconductivity was characterized by electrical resistivity and dc magnetic susceptibility measurements. X-ray diffraction (XRD) and energy dispersion X-ray analysis (EDAX) were used to characterize the structure composition and the sample quality. The resistivity measurements show a double transition to the superconducting state. It is proposed that the grains consist of a core with the optimum cerium content ( [similar to] 0.15) and a shell where the cerium content is different. The homogeneity of the samples was estimated through the determination of the slope of resistivity in the superconducting transition region (d?/dT). Ce content is higher and it is more homogeneously distributed in the samples treated at higher temperatures. EDAX analysis shows that the quantity of Cu on the surface of the samples increases with the temperature of the reduction process.

2

Mikroskopowe techniki analizy powierzchni

Sadowski W., Klimczuk T.

Zeszyty Naukowe Instytutu Maszyn Przepływowych Polskiej Akademii Nauk w Gdańsku

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2002

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nr 524/1483

61--70

PL

W pracy przedstawiono przegląd wybranych aspektów związanych z badaniami powierzchni oraz mikroskopowych metod pomiarowych.

3

Influence of reduction process on the structure and properties of bismuth-silicate glasses.

Trzebiatowski K., Witkowska A., Klimczuk T

Optica Applicata

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2000

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Vol. 30, nr 4

677-683

EN

We report on the investigations into the kinetics of hydrogen reduction process, and some other reduction-related phenomena in the 0.3 Bi/sub 2/O/sub 3/ 0.7 SiO/sub 2/ glass. Use has been made of the various experimental methods, such as measurements of DC electrical conductivity, MIR, DSC and optical microscopy. The reduction process has been shown to lead to significant changes in the physical properties of the near-surface layer of glasses under consideration. The near-surface layer, originally dielectric, becomes semiconducting. Within the reduced layer a granular structure appears. We suggest that the carrier transport might consist in thermally activated hops between localised centres, which are related to the reduction-induced structural defects.