【摘要】 鉴于银包套的铋系高温超导带材作为电工商品化材料的前景己十分看好 ,我们利用直流电输运的四引线 (DCE)和交流磁化率 (ACS)两种方法从实验和理论上研究了银包套的铋系高温超导带材Bi2 2 2 3/Ag的超低频和低频交流损耗 (Q)及数值模拟 .测量频率范围从0 .0 0 1到 2 0 0Hz.在超低频和低频范围内 ,也就是低的磁场和电流扫描速度时 ,两种方法的结果相一致 ,Q随频率增加 .但是在较高一点的频率下ACS方法测量到Q随频率增加而减小 .然而 ,DCE方法却发现Q随电流扫描速度增加而单调地增加 .数值模拟研究的结果证明 ,上述两种实验方法所得到的结果可以用巨磁通蠕动理论予以解释 .我们的研究结果说明了电输运方法和磁测量方法各有一定的特征 .更多还原

【Abstract】 Losses of Ag Bi2223 tape at 77K in low frequency range (0.001Hz～200Hz) were obtained through two experimental methods: V-I characteristics (DCE) and AC susceptibility (ACS) measurement. The effects of sweeping rate of applied current d I /d t (frequency f ) on losses were observed in these two measurements. In super low frequency range, losses increased with the increasing d I /d t(f) in both methods. With increasing frequency higher than 90Hz, losses obtained by ACS method decreased with increasing frequency. But losses obtained by DCE always increased with increasing d I /d t . To understand these experimental results, numerical simulation based on the collective creep model of the vortex glass was carried out. The numerical results qualitatively agree with the experimental ones, demonstrating that there exists different dependence of losses on sweeping rate between DCE method and ACS method.更多还原