samples of high temperature superconductors(Bi2 Ba2 Ca1 Cu2 O7-δ) [System2212] were prepared by solid state reaction method with different sintering temperature (i.e790,830,860,890). C°
X-ray analysis techniques were used to examine the structure of the compound, the study showed ,that the sample prepared during sintering temparture at 860 ċ exhibite tetragonal phase with lattice parameter, (a=b=5.43A° ,c=31.55 A°) while the compound prepared at 890C° Exhibit achange of structure from (tetragonal to orthorhombic) phase this is due to decreasing in(c) axise and increasing in the other two axises (a,b)and the value of lattice parameters were
a=5.45A° , b=5.48A° ,c=30,9 5A°
Electric resistivity method were used to determine the critica temperature T
of these compounds using liquid nitrogen cryostat
the compounds prepared at [790,830,860 and 890]. C°Showed Tc volues of [89, 101.5,121.0 and85]k respective and the values of Oxygen content is[6.25,6.43,6.51,and6.75]
The change of TC values can be explained on the basis that increasing the sintering temperature produces a more uniform crystal structure and an increased oxygen content in the compound .