Effect of additives on the morphology and superconductivity of YBa2Cu3Osub(6+x) ceramic materials

The effect of the addition of 0-15 wt.% alumina powder on the grain size, morphology and superconducting properties of sintered YBa2Cu3Osub(6+x) was investigated as a function of alumina concentration in the composites. The results suggest that the grain size of YBa2Cu3Osub(6+x) decreases with an increase in the additive concentration. Some surface erosion of the YBa2Cu3Osub(6+x) grains was also noticeable in Al2O3/YBa2Cu3Osub(6+x) composites. The results also indicate that the additive tends to stabilize the nonsuperconducting tetragonal phase of the YBa2Cu3Osub(6+x) at the expense of the superconducting orthorhombic crystal phase. (author). 7 refs., 4 figs