熔融织构(Nd-Eu-Gd)-Ba-Cu-O超导体的各向异性磁通跳跃及其不稳定性研究

对c轴择优取向的熔融织构样品(Nd_0.33Eu_0.33Gd_0.33) Ba₂Cu₃O_7-δ（含Gd(211)相）的磁通跳跃现象进行 了系统研究.结果表明，在外加磁 场平行于样品c轴条件下，在2到3K的温度范围内明显观测到了部分磁通跳跃现象，而 在5K及以上温区并未出现.在磁场垂直于样品的c轴情况，在2K到T_c的整个温 区都没有观察到磁通跳跃现象.这种各向异性磁通跳跃现象可归因于各向异性钉扎力和几何 退磁因子的结果.随着温度的增加，磁通跳跃数目减少，且M(H)曲线的第三象限是磁通 跳跃的最不稳定过程.最后，研究了磁通跳跃对磁场扫描速率的依赖关系，并讨论了磁通蠕 动对磁通跳跃的影响.关键词：0.33Eu_0.33Gd_0.33)Ba₂Cu₃O_7-δ超导体')" href="#">(Nd_0.33Eu_0.33Gd_0.33)Ba₂Cu₃O_7-δ超导体OCMG方法磁通跳跃

Flux jumps in textured ( Nd0.33 Eu0.33 Gd0.33 ) Ba2Cu3O7- δsuperconductor with high content Gd-211 phase

Flux jumps behavior in textured (Nd_0.33Eu_0.33Gd_{0.33)Ba2Cu3O7-δ （with high content of Gd-21 1 phase） have been studied. With the magnetic field parallel to the c axis, partial flux jumps have been obser ved in the temperature range 2—3K, and there were no jumps found above 5K. When ab plane is parallel to the field direction, no flux jumps have been observ ed in the whole temperature range (from 2K to Tc). The anisotropi c flux instability may be due to the anisotropic pinning force and geometrical demagnet ization factor. As the temperature increases,the number of flux jumps is decreas ed, and the third quadrant of M(H) curve is the most flux instability quadra nt. Finally we have studied the magnetic field sweep rate dependence of flux jum p, and discussed the influence of flux creep on flux jump.}