Partial substitution of calcium in Bi-Sr-Ca-Cu-O superconductor

摘要

Chemical substitutions may change structural and physical parameters in HTS. Substituents influence formation of Bi-2223 phase, pinning centers, intergrain connection and change hole carrier concentration. Bulk samples with partial substitution of calcium in Bi_(3.2)Pb_(0.8)Sr_4Ca_(5-y)M)xCu_7O_y by 5 B elements (M = V, Nb, Ta), x = 0-0.8 were prepared by solid state reaction in air. Resistivity and magnetic susceptibility measurements evaluated superconducting properties. Phase composition was checked by X-ray diffraction