(Sm0.33Eu0.33Gd0.33)Ba2Cu3O7-δ超导体磁通钉扎力的标定

Scaling of Flux Pinning Force in (Sm_(0.33)Eu_(0.33)Gd_(0.33))Ba_2Cu_3O_(7-δ) Superconductors

用振动样品磁强计测量了熔融织构(Sm0.33Eu0.33Gd0.33)Ba2Cu3O7-δ+40mol%(SmEuGd)2BaCuO5超导体从65K到87K的等温磁滞回线,外加磁场平行于样品的c-轴,最高达到8T。所有的临界电流密度曲线都显示出第二峰效应。磁通钉扎力Fp不能由一个单一的函数进行标定,结果表明,有两种不同的钉扎机制在超导体中共同作用,一种是由于RE-Ba和RE-RE交换所引起的△Tc型钉扎中心,它主要在高场时起作用,负责样品的第二峰效应,另一种是其中含有(SmEuGd)211粒子所引起的正常相面和点钉扎,它随着磁场的增加很快降为零。

The magnetization of top-seed melt processed （Sm0.33Eu0.33Gd0.33） Ba2Cu3O7-δ＋40mol% （SmEuGd）2BaCuO5 superconductor has been investigated by vibrating sample magnetometer over a wide temperature range from 65 K to 87 K. The field dependence of the critical current density for a fix temperature shows the second peak effect. The pinning force Fp cannot be scaled by a single function. The results imply that there is an overlapping of two contributions originating from separate pinning mechanisms： one is the △Tc-type pinning centre originating from the RE–Ba and RE–RE substitution responsible for the second peak, and the other is a normal surface and point-pins by （SmEuGd）211 inclusions which is active mainly at low fields and vanishes rapidly with increasing field.