熔融织构YBCO块材表面的磁感应强度在空间的分布和随时间的变化可以用磁光图像观测.熔融织构YBCO块材的l临界电流密度成功地由饱和抗磁场确定.局域电流密度随时间变化的反常行为从不同磁通动力学模型随空间的时间的转换理解.Bi-2223/Ag带材超导芯中的片晶中的电流密度在67K可达1.5×105A/cm2.由剩余磁感应强度的分布和超声振荡后的碎片证实的超导芯中的网状弱超导区是限制Bi-2223/Ag带材临界电流密度的主要原因.
The magnetic inductionon Bz ( x, t) the surface of the melt texture growth YBCO bulk as function ofspatial location and time were observed by magneto-optic imaging. The critical current density was suc-cessfully determined by the saturated diamagnetic field. The local current density was determined by thegradient of the magnetic induction. The unusual behavior of the local current density as function of timewas understood by the different vortex dynamics models crossover with location and/or time. The currentdensity in the slab-like crystals in the filaments in Bi-2223/Ag tapes reaches 1.5 × 105A/cm2 at 67K.The netlike weak superconducting regions, which were demonstrated by the magnetic images of the rem-nant field and small broken pieces of filaments after 10 sec ultrasonic vibration, must be the main cur-rent-limiting mechanism in Bi-2223/Ag tapes.
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