THE SURFACE CHARACTERIZATION AND STABILITY OF PB-DOPED HG-BASED HTSC

The stability of the homologous series of mercury copper oxide superco nductors is still a serious problem that receives attention from scien tists all over the world. In this paper, we show that Pb-doping in Hg- 1223 can improve the thermal stability of the system. The transition t emperature, as well as the flux pinning effect of the system can be en hanced. The surface characterization was performed by means of Auger e lectron spectroscopic (AES), X-ray photoelectron spectroscopic (XPS) a nd sputtered neutral-particle mass spectroscopic analyses (SNMS). The results of our experiment indicate that the Pb-enriched regions, toget her with the Hg deposition on the surface of the ceramic sample, play the role of nux pinning centres to resist the flux creep.