Water reactivity of (Y,Ca)(Ba,La)(2)CU3Ox superconductors

Water reactivity of Y1-zCazBa2-zLazCu3Ox (YCBLCO, 0 less than or equal to z less than or equal to 0.6) superconductors has been investigated employing R-T measurements, X-ray diffractometry and scanning electron microscopy. T he stability of YCBLCO superconductors in water environments was increased with degree of cation cosubstitution up to z = 0.6. The YCBLCO sample with z = 0.6 showed slight change in resistivity, T-c and surface morphology aft er the water treatment over a period of 300 h. The enhanced stability seems to be attributed to the tetragonal structure in which oxygen in the Cu-O c hain layer was randomly distributed. (C) 2001 Elsevier Science B.V. All rig hts reserved.