Ag掺杂对YBCO烧结靶性能的影响

用固相反应法制备了掺Ag的和不掺Ag的YBCO烧结靶,X射线衍射对样品进行结构及相分析,结果表明,Ag掺杂可以降低靶材的烧结温度,更有利于c轴取向的YBCO超导体的生成;SEM及能谱分析样品断口形貌及成分发现,Ag主要分布在YBCO颗粒的缝隙中,易于形成SNS(YBCO朅g朰BCO)结,克服弱连接增强晶粒间的耦合,提高临界电流密度Jc. 用标准四引线法测量样品的Tc和Jc确实发现掺Ag靶材的Jc要比不掺Ag的约高一个数量级,但Tc相差不多. 掺Ag的靶材较致密,孔洞少,暴露在空气中和在激光作用下不易失超,所以Ag能有效提高YBCO烧结靶的稳定性,延长其使用寿命,对PLD镀膜有重要意义.

On Effect of Ag2O Addition on Superconducting Performance of YBCO Bulk

Bulk-superconducting samples with Ag doping and without Ag doping were prepared by solid-state reaction method. The authors used X-ray diffraction to analyze texture and phase purity of samples. The results show that the Ag2O addition is in favor of decreasing sintering temperature and forming c-axis aligned YBCO bulk. SEM and EDAX were respectively used to evaluate the fracture morphology, the distribution of Ag and component of samples. It has been shown that Ag atoms located among YBCO particles help to form SNS knots, which can strengthen intergranular coupling and enhance the critical current density Jc. Tc and Jc were measured using a standard four-probe method by a 1 μv / cm2 criterion at 77 K. The results show that Ag doping has no noticeable effect on the Tc of samples, but increases the samples' Jc by one order. In addition, compared with bulk-superconducting samples without Ag doping, the samples with Ag doping are denser, with fewer pores, and are less possible to lose superconductivity in air and laser. Thus, Ag2O addition in the bulk can strengthen the stability of superconducting samples effectively and make it have a longer life.