超伝導性Bi₂Sr_2-xLa_xCuO_yの結晶作製と評価

抄録

Bi-2201 system oxide superconducting crystals with or without doped La are grown by Verneuil method and travelling melt zone method by CO₂-laser heating. Single crystals though tiny reveal microstep line structures on their surfaces produced by lateral crystal growth mechanism. The fundamental step height is measured as 12Å which is equal to the half unit cell dimension. Bi, Cu and O, respectively, distribute nearly uniformly in the crystal, while Sr and La do not display uniform distribution. As an interesting characterics the concentration of Sr and La is complementary between the two. This suggests the a replacement of Sr in the crystal lattice by La is taking place. Occasionally magnetic susceptibility and electrical resistivity proved the occurrence of superconductivity but the reproducibility is rather inferior.