高铅掺氟Bi系超导体的研制

STUDY ON THE PREPARATION OF F-DOPED Bi-SYSTEM SUPERCONDUCTORS WITH HIGH CONTENT OF LEAD

本文首次报道了五种高铅量Bi系超导体Bi_(2-n)Pb_nSr_2Ca_2Cu_3O_(y-x)F_x(n=1.0,1.2,1.4,1.6,1.7)的制备,x在1.0～1.4的范围内,n依次取上述值时。超导体的T_(co)分别为113.6K,112K,104K,88K,78K。X射线粉末衍射,红外光谱等分析表明,n=1.0～1.4时超导体仍具有2223相结构特征;n=1.6,1.7时表现出新的结构特点,此外从化学动力学观点初步探讨了CuF_2,PbO在超导相形成过程中的作用。

Five kinds of superconductors were directly synthesized with CuF_2 substituting parts of CuO. According to the nominal composition Bi_(2-n)Pb_nSr_2Ca_2Cu_3O_(y-x)F_y, as n was equal to 1.0, 1.2, 1.4, 1.6, 1.7, and x ranged from 1.0 to 1.4, T_(co) of samples were 113.6 K, 112 K, 104 K, 88 K, and 78 K respectively. The result of X-ray powder diffraction, infrared spectra showed that superconductors with Pb amount equal to 1.0, 1.2, 1.4 still kept 2223 superconductive structure and they exhibited new structural features as Pb amount equaled 1.6, 1.7. The effect of CuF_2 and PbO on the formation of super conducting phase were stud- ied based on chemical kinetics.