EFFECT OF CODOPING SB AND V TO THE BIPBSRCACUO SYSTEM

With XRD, R- T curves, and a.c chi measurements, the doping and codoping effects of Sb and V to a Cu-deficient Pb-doped Bi system have been studied. A sample singly doped with V possesses a T(c) about 2 K lower than that of a sample singly doped with Sb. This is attributed to the different sites of their substitution. It was observed that for promoting 2223 phase formation, Sb and V works cooperatively, and the codoping of Sb may enhance the 2223 phase formed. With a low doping level of Sb, the optimum doping amount of V is 0.3, i.e., with a nominal composition of Bi1.5Pb0.3Sb0.06Sr2Ca2Cu2.4V0.3Oy. A sample in which the 2223 phase is the dominant phase and which has a zero resistance transition temperature of 105 K has been obtained.