| 要約: | The superconducting Tl 0.8Bi 0.2Sr 2Ca 0.8Y 0.2Cu 2O 7 powder prepared from chemical route was mixed with varying amounts of nano-sized MgO powders (x=0 to 0.50 wt. %) to form bulk superconducting composites. XRD results show that the addition of 0.15 wt.% nano-MgO is accompanied by an increase in 1212-phase and the disappearance of SrCO 3 impurity. SEM investigations revealed more regular-shaped and smaller grains microstructure for MgO added samples in contrast to MgO-free sample which revealed irregular shaped grains. EDS showed homogenous distribution of Mg for all MgO-added samples with the exception of x=0.50 where agglomeration of MgO particles were observed. However, MgO added samples exhibit lower zero-resistance critical temperature, T c zero than the MgO-free sample. © (2012) Trans Tech Publications, Switzerland.
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