材料期刊网

The major limitations of Bi-system superconductor application are the intergrain weak links and weak flux pinning capability. In order to promote the practical application of Bi-system superconductor, effective flux pinning centers must be artificially introduced into HTS to enhance the flux pinning capability. With those goals, we have investigated the effects of nanometer-sized ZrO2 addition on flux pinning capability of the bulk Pb-doped Bi-2223 by using of X-ray diffraction (XRD), DC resistivity, rho, AC susceptibility, c, and magnetic hysteresis loops measurements. We have prepared samples by Bi,Bi1.8Pb0.4Sr2Ca2.2Cu3O10+y (nano-ZrO2)(x) with x range from 0 to 0.5. The results show that, with the increasing of x-, the T-c (onset) drops down gradually. However, the measurements of the critical current density, J(c), show that appropriate amount-doped nano-ZrO2 greatly enhance the values of J(c) under magnetic fields. According to the results of XRD patterns, there are slight reflection peaks of ZrO2-related nonsuperconducting compounds. It is believed that these nonsuperconducting ZrO2-related compounds act as effective flux pinning centers. (C) 2000 Elsevier Science B.V. All rights reserved.