Abstract:
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 Ag
2O 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 / cm
2 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, Ag
2O addition in the bulk can strengthen the stability of superconducting samples effectively and make it have a longer life.