Effect of Sintering and Annealing Temperatures on the Critical Temperature and Electrical Resistivity of Bi2Ba2Ca2Cu3O10+δ
Abstract
Samples of the high temperature superconducting system, Bi2Ba2Ca2Cu3O10+δ, were prepared by using the solid state reaction method with different sintering temperatures of 810, 830, 850, 870 and 890oC. The electrical resistivity measurements exhibited that the sintering and annealing conditions have major effects on the critical temperature of the superconducting compound. The sample prepared at 850oC has a critical temperature Tc ≈110 K, meanwhile the sample prepared at 870oC has a critical temperature ≈80 K. However, the sample which was prepared at 890oC showed semiconducting behavior with an activation energy of 6.40 meV. The effect of annealing onthe critical temperature has been investigated using the sample prepared at 850oC. The value of Tc at the annealing temperature of 400oC rises from 110 K to 138 K with increasing the annealing time from 24 hrs to 72 hrs. This increase might be due to the increase of oxygen content or tothe intergrowth of a large number of Cu-O layers in the cell.
Keywords: High temperature superconductors; Semiconductors; Sintering; Annealing; Electrical resistivity.
