The Effect of Pb Addition on Superconductivity in Bi-Sr-Ca-Cu-O

Abstract

The effect of Pb addition on superconductivity was studied on the systems with nominal compositions (BiPb x )2Sr2Ca2Cu3O y , (Bi1-x Pb x )2Sr2Ca2Cu3O y and (Bi1-x Pb x )2Sr2Ca2Cu3.6O y . The melting point decreases monotonically from ∼880 to ∼860°C as x increases from 0 to 0.45 in the systems, while the volume fraction of the high-T c phase (HTP) and the offset value of T c show a peak around x=0.2∼0.3. Further increase in x produces the Ca2PbO4, leading to the suppression of the HTP. The amount of Pb suitable for the formation of the HTP is limited by the competition between the reaction to form the HTP by the catalytic effect of Pb and the one to form the Ca2PbO4.

The Role of Cooling Condition on the Superconducting Properties of Tl<sub>2-x</sub>Hg<sub>x</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10+δ</sub> System

“…Two sets of samples were produced for each superconducting compound, the first set of samples was allowed to cool to room temperature in a tube furnace that has programmable controller with a cooling rate 275 K/min, while the second set of samples was removed from the furnace and quenched in air. However, certain amount of Hg is necessary for the occurrence of this reaction, while excessive Hg substitution promotes another reaction, which is likely to assist the formation of low-T c phase instead of the high-T c phase [14] [15] [16].…”

Effect of Sintering Temperature on Bi2-xCuxPb0.3Sr2Ca2Cu3O10+δ Superconductors

“…The lattice parameters of the fundamental unit cells, determined by X-ray diffraction, are as follows: Recently, the variation of hole concentration by cation substitution is increasingly used to investigate the mechanism of high T c superconductivity in the cuprate oxides. Partial substitution for Bi +3 by ions of various radii and valance such as Pb +2 in Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ compound may be affect the high T c -phase formation, chemical stability and the superconducting properties [5][6] .…”

Effect of (CuPb)x Substitution on Tc of Bi2-x(CuPb)x Sr2Ca2Cu3O10+δ Superconductors

“…The lattice parameters of the fundamental unit cells, determined by X-ray diffraction, are as follows: Recently, the variation of hole concentration by cation substitution is increasingly used to investigate the mechanism of high T c superconductivity in the cuprate oxides. Partial substitution for Bi +3 by ions of various radii and valance such as Pb +2 in Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ compound may be affect the high T c -phase formation, chemical stability and the superconducting properties [5][6] .…”