材料期刊网

The temperature dependence of resistivity (R-T) for three whiskers has been measured. in the three R-T curves, two steps in the resistance drop are observed, at 107 K and 80 K, which are attributed to the (2223) high-T(c) phase and the (2212) low-T(c) phase respectively The x-ray diffraction pattern for the whiskers shows that their main phase is the low-T(c) phase, and their minor phase is the high-T(c) phase. The zero-magnetic-field critical current density of a whisker is 29 000 A cm-2 at 63.4 K, which is much higher than that of an annealed glass and a sintered sample. The differences in J(c) among the three kinds of material were found to be related to their microstructures.