Publication
Zeitschrift für Physik B Condensed Matter
Paper

Possible high Tc superconductivity in the Ba-La-Cu-O system

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Abstract

Metallic, oxygen-deficient compounds in the Ba-La-Cu-O system, with the composition BaxLa5-xCu5O5(3-y) have been prepared in polycrystalline form. Samples with x=1 and 0.75, y>0, annealed below 900°C under reducing conditions, consist of three phases, one of them a perovskite-like mixed-valent copper compound. Upon cooling, the samples show a linear decrease in resistivity, then an approximately logarithmic increase, interpreted as a beginning of localization. Finally an abrupt decrease by up to three orders of magnitude occurs, reminiscent of the onset of percolative superconductivity. The highest onset temperature is observed in the 30 K range. It is markedly reduced by high current densities. Thus, it results partially from the percolative nature, bute possibly also from 2 D superconducting fluctuations of double perovskite layers of one of the phases present. © 1986 Springer-Verlag.

Date

01 Jun 1986

Publication

Zeitschrift für Physik B Condensed Matter

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