Superconductivity around 90K is observed in mixed and single phase system of LnBaCuO (Ln = Y, Ho, Er). Resistivity, X-ray powder diffraction and AC susceptibility measurements were carried out on samples of the mixed phase systems Ln2-xBaxCuO4-y (Ln = Ho, Er), Y1.2Ba0.8Cu1+xO4+x-y(0<x<5) and single phase system Ba2LnCu3O7 (Ln = Y, Ho, Er). Ln2-xBaxCuO4-y consists of Ba2LnCu3O7, BaCuLn2O5, Cu2Ln2O5 and starting materials and shows a small diamagnetic signal below Tc in the temperature dependent AC susceptibility. Y1.2Ba0.8Cu1+xO4+x-y is a mixture of Ba2YCu3O7, BaCuY2O5 and CuO and also indicates a small diamagnetic signal at 92K. Interesting resistivity anomalies occur in the Y1.2Ba0.8Cu4O7-y and Ho0.8Ba1.2CuO4-y composites including large drops in the resistivity at ∼220 and ∼120K, respectively. The pure compounds, Ba2LnCu3O7 (Ln = Y, Ho, Er) show sharp resistive superconducting transitions and bulk Meissner effects of 90%.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry