No abstract

The effect of Bi in (Y 1−x Bi x )Ba 2 Cu 3 O 7−δ for x = 0.00-0.30 has been investigated by powder X-ray diffraction method, dc electrical resistance measurements and scanning electron microscopy. The resistance versus temperature curves showed metallic behavior for samples with x ≤ 0.20 and semiconductor-like behavior for x = 0.25 and 0.30. The resistance versus temperature curves showed onset transition temperature (T c onset ) between 89 and 93 K and a broadening of the superconducting-transition width with increasing Bi content for all samples. T c onset decreased linearly indicating a pair-breaking mechanism in T c suppression for x = 0 to 0.3. The non-systematic broadening of the transition width may be due to the inhomogeneities in the samples as Bi content was increased. No substitution of Bi for Y was observed.