Article ID Journal Published Year Pages File Type
1814254 Physica B: Condensed Matter 2008 6 Pages PDF
Abstract
Gold (Au) diffusion in superconducting Bi1.8Pb0.35Sr1.9Ca2.1Cu3Oy was investigated over the temperature range 500-800 °C by the energy dispersive X-ray fluorescence (EDXRF) technique. It is found that the Au diffusion coefficient decreases as the diffusion-annealing temperature decreases. The temperature dependences of Au diffusion coefficient in grains and over grain boundaries are described by the relations D1=6.7×10−5exp(−1.19 eV/kBT) and D2=9.7×10−4exp(−1.09 eV/kBT), respectively. The diffusion doping of Bi-2223 by Au causes a significant increase of the lattice parameter c by about 0.19%. For the Au-diffused samples, dc electrical resistivity and transport critical current density measurements indicated the critical transition temperature increased from 100 to 104 K and the critical current density increased from 40 to 125 A cm−2, in comparison with those of undoped samples. From scanning electron microscope (SEM) and X-ray diffraction (XRD) measurements it is observed that Au doping of the sample also improved the surface morphology and increased the ratio of the high-Tc phase to the low-Tc phase. The possible reasons for the observed improvement in microstructure and superconducting properties of the samples due to Au diffusion are also discussed.
Related Topics
Physical Sciences and Engineering Physics and Astronomy Condensed Matter Physics
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