| Popis: |
In this paper, we present a study on the critical current density and magnetic relaxation behavior of the Mo-substituted BiSrCaCuO system. The Bi 2 Sr 2 Ca 2 Cu 3− x Mo x O 10+ y , where x =0, 0.5, 1.0 and 1.5 have been fabricated using glass-ceramic technique. It was found that the Mo-substitution to the BiSrCaCuO system lead to the formation of pinning centers and hence an increase of critical current density. The magnetic relaxation experiments were performed to understand physical phenomena behind of flux motion. Time dependence of the magnetization exhibited thermally activation flux motion in the samples. It was found that the normalized magnetic relaxation rate, S , did not vary linearly with temperature, especially at high temperatures, which is attributed to the collective creep theory. In addition, the characteristic pinning energy, U e /K B , in the samples was calculated using Maley's method. Correlation between the pinning energy and the magnetization showed that obtained experimental results can be fitted to the collective creep theory. |
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