Superconductivity in YBa2Cu3O7- delta-ZrO2systems

Abstract
The effect of ZrO2 addition on the superconducting properties of YBa2Cu3O7- delta superconductors has been investigated by temperature-resistance measurements and X-ray diffraction studies. The results revealed that ZrO2 additions up to 2.0 wt.% do not have any detrimental effect on the superconducting properties of YBa2Cu3O7- delta . It is also found that the widely accepted procedure of slow cooling or annealing at 600 degrees C for several hours for oxygenation of samples is not essential to obtain superconductivity in the Zr-doped samples. The superconducting transition (92 K) was obtained by directly quenching the doped specimen from the sintering temperature of 950 degrees C in an oxygen atmosphere. The tetragonal to orthorhombic transformation took place within seconds in the doped samples, indicating that the rate of oxygen absorption has been tremendously increased in the ZrO2-doped YBa2Cu3O7- delta . Undoped samples quenched in air were always tetragonal and non-superconducting.