Microstructure, AC susceptibility and electrical properties of K2CO3 added YBa2Cu3O7−δ superconductor

Abstract

The effect of potassium carbonate addition on YBa2Cu3O7-δ is reported. Samples with starting composition YBa2Cu3O7-δ(K2CO3)x were prepared using the solid reaction method with x = 0, 0.1, 0.3, 0.4, 0.5, 1.0 and 5.0 wt%. The four-point probe electrical resistance, AC susceptibility, X-ray diffraction method and field emission scanning electron microscopy (FESEM) were used to characterize the samples. Addition of K2CO3 did not affect the orthorhombic structure and the microstructure. The average grain size was between 12 and 13 µm and not affected by the addition of K2CO3. A slight decrease in the onset transition temperature was observed for x ≤ 1.0. The x = 5.0 wt% samples showed a significantly reduced transition temperature. Samples with x = 0 to 0.5 wt% showed a peak in the imaginary part of the complex susceptibility known as the peak transition temperature, Tp of around 85–86 K while the x = 5.0 wt% samples showed Tp reduced to 82 K . The critical current density at Tp was between 15 and 19 A/cm2. This work showed that K2CO3 and KClO3 have totally different effects on YBa2Cu3O7-δ superconductor.