Resistivity－temperature characteristics of sol gel YBa₂Cu₃O_y samples synthesized in flowing oxygen atmosphere

The relationship of resistivity versus synthesizing temperature of sol gel YBa_2Cu_3O_y samples was studied when prepared under flowing oxygen conditions. A set of high-temperature \rho－T curves was obtained for the whole process. After the sample finished the test measuring, its resistivity was \rho_300=9.83\times10^-3 \Omega\cdotcm at room temperature. The \rho－T curve also showed that the orthorhombic－tetragonal phase transformation of sol-gel YBa_2Cu_3O_y sample occurred at 581℃ for the sample in the rising temperature process, but at 613℃ in the cooling process, lower than that of the samples made by using the conventional powder metallurgy methods.