The effect of MgCO3 addition on the superconducting properties of Bi2223 superconductors

MgCO3 particles were introduced into Bi1.66Pb.34Sr2Ca2Cu3O10-delta powder in various weight fractions. Bulk samples were made from the Bi2223/MgCO3 powder by the conventional solid state reaction method. The superconducting properties of samples for different amounts of MgCO3 have been investigated by means of X-ray diffraction, magnetoresistivity. Room temperature X-ray diffraction studies show that there exists two phases, i.e. Bi2223 and Bi2212 in analyzed samples. The volume fraction of Bi2223 phase decreases with increasing MgCO3 content. It is observed that the lattice parameter c decreases with increasing MgCO3 content, but a (and/or b) axis does not change considerably. The temperature at which the resistivity becomes zero decreases with increasing dopant content and also with increasing applied magnetic field. The normal state resistivity regularly decreases with the increase in MgCO3 addition. (C) 2009 Elsevier B.V. All rights reserved.