THE INFLUENCE OF PB ,AL DOPED ON THE HIGH- TEMPERATURE SUPERCONDUCTOR (BI2-SR2-CA2-CU3- O10+Δ)

Abstract

 A ceramic superconductor compounds with the composition Bi2Sr2Ca2Cu3O10+δ were prepared alone or substituted by pb doped(Bi2-xPbxSr2Ca2Cu3O10+δ ) samples with different   values of x =(0.1,0.35,0.4), and Al  doped(Bi2 AlxSr2Ca2Cu3O10+δ ) samples with different   values of x=(0.1,0.2,0.3) .The solid state reaction method was used for samples preparation . From the principle routs like Bi-2223,Ca2CO3 and CuO with high purity 99.999% . Superconducting phase was achieved by sintering (860oC) for (16  hours) .The slow cooling rate (1oC/min).was very important to the formation of superconducting time .The Bi-based system was multi phases . Different measurement such as resistivity measurement , X-ray diffraction(XRD) and Scanning Electron Microscope(SEM)  were made to show the improvement in the superconductivity of the high phase. The crystal structures of stable superconducting  compound of  Bi2Sr2Ca2Cu3O10+δ was orthorhombic with lattice constant about a=5.394oA,b=5.346oA,c=30.753oA for low Tc phase and a=5.394oA,b=5.311oA,c=37.182oA for high phase .The critical temperatures (Tc) of the HTSC Bi2Sr2Ca2Cu3O10+δ were obtained to be Tc value for the un doped sample and for  Pb, Al doped systems respectively and Scanning Electron Microscope(SEM)  images showed formation plate-like or flake –like texture phases in superconducting samples