Akademik Veri Yönetim Sistemi
JOURNAL OF ALLOYS AND COMPOUNDS, cilt.291, ss.269-275, 1999 (SCI-Expanded)
We have studied the superconducting properties of nominal composition of Bi1.6Pb0.4Sr2Ca3Cu4Ox (2234) rods grown by the resistive-heat floating-zone (RHFZ) method. Oriented crystalline samples of 2212 were successfully obtained from the 2234 glassy rod using this method. In order to improve the physical properties of superconductors, the influence of growth rate on their microstructure has been analyzed, and it was found that the ratio of superconducting phase of 2212 increased with the lowest growth rates which results in better grain alignment in the samples. The magnetic behavior of textured BSCCO was determined by measurements of the resistivity, rho, in an external magnetic field. The normalized resistance as a function of temperature and of applied field of the samples was plotted and the low temperature peaks show the energy dissipation due to the flux flow within the grains at a given field. In addition, the activation energy, U-0, for thermally activated flux flow (TAFF) was estimated for samples from the slope of the Arrhenius plot of In rho vs. 1/T. It was found that the activation energy of samples decreases with increasing magnetic field. (C) 1999 Elsevier Science S.A. All rights reserved.