【摘要】 利用Ｘ 射线衍射、扫描电镜和ＳＱＵＩＤ 磁强计研究了粉末熔化（ＰＭＰ）ＹＢａ２Ｃｕ３Ｏｙ 和掺Ｇｄ 的ＹＢＣＯ 超导体的微结构，超导性能、磁通钉扎特性及鱼尾效应等，发现在掺杂Ｇｄ 的样品中当温度低于７０ Ｋ 时出现鱼尾现象（ Ｈ⊥ｃ） ，而在纯ＹＢＣＯ 中无鱼尾出现．添加Ｇｄ 有助于提高Ｊｃ，增强钉扎，并认为由掺Ｇｄ 所引起的Ｙ２ＢａＣｕＯ５ 粒子尺寸的减小，应力场钉扎和磁性钉扎是Ｊｃ 增加的原因更多还原

【Abstract】 Superconducting properties and fishtail effect of powder melting processed Y\|Gd\|Ba\|Cu\|O have been investigated through X\|ray diffraction pattern,a.c.susceptibilty and SQUID magnetometer.It is found that the fishtail effect can be observed in Gd\|doped YBCO ( T< 70K, H⊥c ) while no fishtail appears in the pure YBCO sample. J c and flux pinning are improved by the partial substitution of Gd for Y.It is expected that the reduction of the Y\-2BaCuO\-5 size,stress field pinning and magnetic pinning are responsible for the enhancement of J c.更多还原