Current-voltage characteristics of melt-textured YBCO obtained from the field-sweep rate dependence of magnetization

We investigated current-voltage (I-V) characteristics in melt-textured YBCO sheets by measuring the field-sweep rate /spl beta/ dependence of magnetization M. We used a previously developed method that corrects for the current density distribution in the specimen [Y. Mawatari et al., Appl. Phys. Lett., vol. 70, 2300 (1997)]. For a wide temperature and field range (60-80 K, 0.2-5.0 T) the I-V curves followed a power-law behavior that often has been observed in high-T/sub c/ superconductors. We also investigated the relaxation of magnetization, flux creep. The time dependence of M also followed a power-law behavior, which was as expected because of the power-law I-V characteristics.